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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html lang="en" xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type" content="text/html;charset=UTF-8"/>
<link rel="icon" type="image/gif" href="/favicon.gif"/>
<link rel="apple-touch-icon" sizes="120x120" href="touch-icon-iphone-retina.png" />
<link rel="apple-touch-icon" sizes="152x152" href="touch-icon-ipad-retina.png" />
<title>Lorem Ipsum</title>
<script type="text/javascript"
src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
</script>
<style type="text/css" id="internal-style">
@import url(hyperpolyglot.css);
</style>
<meta http-equiv="content-type" content="text/html;charset=UTF-8"/>
<meta http-equiv="content-language" content="en"/>
</head>
<body>
<div id="container-wrap-wrap">
<div id="container-wrap">
<div id="container">
<div id="header">
<h1><a href="/"><span>Hyperpolyglot</span></a></h1>
</div>
<div id="content-wrap">
<div id="main-content">
<div id="page-title">Lorem Ipsum</div>
<div id="page-content">
<p><a name="top"></a><em>a side-by-side reference sheet</em></p>
<p><strong>sheet one:</strong> <a href="#grammar-invocation">grammar and invocation</a> | <a href="#var-expr">variables and expressions</a> | <a href="#arithmetic-logic">arithmetic and logic</a> | <a href="#strings">strings</a> | <a href="#regexes">regexes</a> | <a href="#dates-time">dates and time</a> | <a href="#tuples">tuples</a> | <a href="#arrays">arrays</a> | <a href="#arithmetic-sequences">arithmetic sequences</a> | <a href="#two-d-arrays">2d arrays</a> | <a href="#three-d-arrays">3d arrays</a> | <a href="#dictionaries">dictionaries</a> | <a href="#functions">functions</a> | <a href="#execution-control">execution control</a> | <a href="#file-handle">file handles</a> | <a href="#directories">directories</a> | <a href="#processes-environment">processes and environment</a> | <a href="#libraries-namespaces">libraries and namespaces</a> | <a href="#reflection">reflection</a> | <a href="#debugging">debugging</a></p>
<p><strong><a href="/numerical-analysis2">sheet two</a>:</strong> <a href="/numerical-analysis2#tables">tables</a> | <a href="/numerical-analysis2#import-export">import and export</a> | <a href="/numerical-analysis2#relational-algebra">relational algebra</a> | <a href="/numerical-analysis2#aggregation">aggregation</a></p>
<p><a href="/numerical-analysis2#vectors">vectors</a> | <a href="/numerical-analysis2#matrices">matrices</a> | <a href="/numerical-analysis2#sparse-matrices">sparse matrices</a> | <a href="/numerical-analysis2#optimization">optimization</a> | <a href="/numerical-analysis2#polynomials">polynomials</a> | <a href="/numerical-analysis2#descriptive-statistics">descriptive statistics</a> | <a href="/numerical-analysis2#distributions">distributions</a> | <a href="/numerical-analysis2#linear-regression">linear regression</a> | <a href="/numerical-analysis2#statistical-tests">statistical tests</a> | <a href="/numerical-analysis2#time-series">time series</a> | <a href="/numerical-analysis2#fast-fourier-transform">fast fourier transform</a> | <a href="/numerical-analysis2#clustering">clustering</a> | <a href="/numerical-analysis2#images">images</a> | <a href="/numerical-analysis2#sound">sound</a></p>
<p><a href="/numerical-analysis2#bar-charts">bar charts</a> | <a href="/numerical-analysis2#scatter-plots">scatter plots</a> | <a href="/numerical-analysis2#line-charts">line charts</a> | <a href="/numerical-analysis2#surface-charts">surface charts</a> | <a href="/numerical-analysis2#chart-options">chart options</a></p>
<table class="wiki-content-table">
<tr>
<th></th>
<th><a href="#matlab">matlab</a></th>
<th><a href="#r">r</a></th>
<th><a href="#numpy">numpy</a></th>
<th><a href="#julia">julia</a></th>
</tr>
<tr>
<td><a name="version-used"></a><a href="#version-used-note">version used</a></td>
<td><span style="color: gray"><em>MATLAB 8.3</em></span><br />
<br />
<span style="color: gray"><em>Octave 3.8</em></span></td>
<td><span style="color: gray"><em>3.1</em></span></td>
<td><span style="color: gray"><em>Python 2.7</em></span><br />
<span style="color: gray"><em>NumPy 1.7</em></span><br />
<span style="color: gray"><em>SciPy 0.13</em></span><br />
<span style="color: gray"><em>Pandas 0.12</em></span><br />
<span style="color: gray"><em>Matplotlib 1.3</em></span></td>
<td><span style="color: gray"><em>0.4</em></span></td>
</tr>
<tr>
<td><a name="show-version"></a><a href="#show-version-note">show version</a></td>
<td>$ matlab -nojvm -nodisplay -r 'exit'<br />
<br />
$ octave <span style="white-space: pre-wrap;">--version</span></td>
<td>$ R <span style="white-space: pre-wrap;">--version</span></td>
<td>sys.version<br />
np.<span style="white-space: pre-wrap;">__version__</span><br />
sp.<span style="white-space: pre-wrap;">__version__</span><br />
mpl.<span style="white-space: pre-wrap;">__version__</span></td>
<td>$ julia <span style="white-space: pre-wrap;">--</span>version</td>
</tr>
<tr>
<td><a name="implicit-prologue"></a><a href="#implicit-prologue-note">implicit prologue</a></td>
<td><span style="color: gray"><em>none</em></span></td>
<td>install.packages('ggplot2')<br />
library('ggplot2')</td>
<td>import sys, os, re, math<br />
import numpy as np<br />
import scipy as sp<br />
import scipy.stats as stats<br />
import pandas as pd<br />
import matplotlib as mpl<br />
import matplotlib.pyplot as plt</td>
<td> </td>
</tr>
<tr>
<th colspan="5"><a name="grammar-invocation"></a><a href="#grammar-invocation-note">grammar and invocation</a></th>
</tr>
<tr>
<th></th>
<th><a href="#matlab">matlab</a></th>
<th><a href="#r">r</a></th>
<th><a href="#numpy">numpy</a></th>
<th><a href="#julia">julia</a></th>
</tr>
<tr>
<td><a name="interpreter"></a><a href="#interpreter-note">interpreter</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>$ cat <span style="white-space: pre-wrap;">>></span>foo.m<br />
1 + 1<br />
exit<br />
<br />
$ matlab -nojvm -nodisplay -r "run('foo.m')"<br />
<br />
$ octave foo.m</td>
<td>$ cat <span style="white-space: pre-wrap;">>></span>foo.r<br />
1 + 1<br />
<br />
$ Rscript foo.r<br />
<br />
$ R -f foo.r</td>
<td>$ cat <span style="white-space: pre-wrap;">>></span>foo.py<br />
print(1 + 1)<br />
<br />
$ python foo.py</td>
<td>$ cat <span style="white-space: pre-wrap;">>></span>foo.jl<br />
println(1 + 1)<br />
<br />
$ julia foo.jl</td>
</tr>
<tr>
<td><a name="repl"></a><a href="#repl-note">repl</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>$ matlab -nojvm -nodisplay<br />
<br />
$ octave</td>
<td>$ R</td>
<td>$ python</td>
<td>$ julia</td>
</tr>
<tr>
<td><a name="cmd-line-program"></a><a href="#cmd-line-program-note">command line program</a></td>
<td>$ matlab -nojvm -nodisplay -r 'disp(1 + 1); exit'<br />
<br />
$ octave <span style="white-space: pre-wrap;">--</span>silent <span style="white-space: pre-wrap;">--</span>eval '1 + 1'</td>
<td>$ Rscript -e 'print("hi")'</td>
<td>python -c 'print("hi")'</td>
<td>$ julia -e 'println("hi")'</td>
</tr>
<tr>
<td><a name="block-delimiters"></a><a href="#block-delimiters-note">block delimiters</a></td>
<td>function end<br />
if elseif else end<br />
while end<br />
for end</td>
<td>{ }</td>
<td><span style="color: gray"><em>offside rule</em></span></td>
<td> </td>
</tr>
<tr>
<td><a name="stmt-separator"></a><a href="#stmt-separator-note">statement separator</a></td>
<td>; <span style="color: gray"><em>or newline</em></span><br />
<br />
<span style="color: gray">//Newlines not separators after three dots:// <span style="white-space: pre-wrap;">...</span></span><br />
<br />
<span style="color: gray"><em>Output is suppressed when lines end with a semicolon.</em></span></td>
<td>; <span style="color: gray"><em>or sometimes newline</em></span><br />
<br />
<span style="color: gray"><em>Newlines not separators inside (), [], {}, '', "", or after binary operator.</em></span></td>
<td><span style="color: gray"><em>newline or ;<br />
<br />
Newlines not separators inside (), [], {}, triple quote literals, or after backslash: \</em></span></td>
<td> </td>
</tr>
<tr>
<td><a name="eol-comment"></a><a href="#eol-comment-note">end-of-line comment</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>1 + 1 <span style="color: gray">% addition</span></td>
<td>1 + 1 <span style="color: gray"># addition</span></td>
<td>1 + 1 <span style="color: gray"># addition</span></td>
<td>1 + 1 <span style="color: gray"># addition</span></td>
</tr>
<tr>
<th colspan="5"><a name="var-expr"></a><a href="#var-expr-note">variables and expressions</a></th>
</tr>
<tr>
<th></th>
<th><a href="#matlab">matlab</a></th>
<th><a href="#r">r</a></th>
<th><a href="#numpy">numpy</a></th>
<th><a href="#julia">julia</a></th>
</tr>
<tr>
<td><a name="assignment"></a><a href="#assignment-note">assignment</a></td>
<td>i = 3</td>
<td>i = 3<br />
i <- 3<br />
3 -> i<br />
assign("i", 3)</td>
<td>i = 3</td>
<td>i = 3</td>
</tr>
<tr>
<td><a name="parallel-assignment"></a><a href="#parallel-assignment-note">parallel assignment</a></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td><a name="swap"></a><a href="#swap-note">swap</a></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr>
<td><a name="compound-assignment"></a><a href="#compound-assignment-note">compound assignment</a><br />
<span style="color: gray"><em>arithmetic, string, logical</em></span></td>
<td><span style="color: gray"><em>none</em></span></td>
<td><span style="color: gray"><em>none</em></span></td>
<td><span style="color: gray"># do not return values:</span><br />
+= -= *= /= <span style="white-space: pre-wrap;">//</span>= %= <span style="white-space: pre-wrap;">**</span>=<br />
+= *=<br />
&= |= ^=</td>
<td> </td>
</tr>
<tr>
<td><a name="null"></a><a href="#null-note">null</a></td>
<td><span style="color: gray">% Only used in place of numeric values:</span><br />
NaN</td>
<td>NA NULL</td>
<td>None np.nan<br />
<br />
<span style="color: gray"># None cannot be stored in a numpy array;<br />
# np.nan can if dtype is float64.</span></td>
<td><span style="color: gray"># Only used in place of float values:</span><br />
NaN</td>
</tr>
<tr>
<td><a name="null-test"></a><a href="#null-test-note">null test</a></td>
<td>isnan(v)<br />
<br />
<span style="color: gray">% true for '', []:</span><br />
isempty(v)</td>
<td>is.na(v)<br />
is.null(v)</td>
<td>v == None<br />
v is None<br />
<br />
np.isnan(np.nan)<br />
<span style="color: gray"># np.nan == np.nan is False</span></td>
<td>isnan(v)</td>
</tr>
<tr>
<td><a name="cond-expr"></a><a href="#cond-expr-note">conditional expression</a></td>
<td><span style="color: gray"><em>none</em></span></td>
<td>(if (x > 0) x else -x)<br />
ifelse(x > 0, x, -x)</td>
<td>x if x > 0 else -x</td>
<td>x > 0 ? x : -x</td>
</tr>
<tr>
<th colspan="5"><a name="arithmetic-logic"></a><a href="#arithmetic-logic-note">arithmetic and logic</a></th>
</tr>
<tr>
<th></th>
<th><a href="#matlab">matlab</a></th>
<th><a href="#r">r</a></th>
<th><a href="#numpy">numpy</a></th>
<th><a href="#julia">julia</a></th>
</tr>
<tr>
<td><a name="boolean-type"></a><a href="#boolean-type-note">boolean type</a></td>
<td> </td>
<td> </td>
<td><span style="color: gray"># Python:</span><br />
bool<br />
<br />
<span style="color: gray"># NumPy:</span><br />
bool_</td>
<td>Bool</td>
</tr>
<tr>
<td><a name="true-false"></a><a href="#true-false-note">true and false</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>1 0 true false</td>
<td>TRUE FALSE T F</td>
<td>True False</td>
<td>true false</td>
</tr>
<tr>
<td><a name="falsehoods"></a><a href="#falsehoods-note">falsehoods</a></td>
<td>false 0 0.0<br />
<span style="color: gray"><em>matrices evaluate to false unless nonempty and all entries evaluate to true</em></span></td>
<td>FALSE F 0 0.0<br />
<span style="color: gray"><em>matrices evaluate to value of first entry; string in boolean context causes error</em></span></td>
<td>False None 0 0.0 '' [] {}</td>
<td>false</td>
</tr>
<tr>
<td><a name="logical-op"></a><a href="#logical-op-note">logical operators</a></td>
<td>~true | (true & false)<br />
<br />
<span style="color: gray">% short-circuit operators:</span><br />
&& @</td>
<td>@</td>
<td>!TRUE | (TRUE & FALSE)<br />
<span style="color: gray"><em>short-circuit operators:</em></span><br />
&& @</td>
<td>@<br />
<br />
##gray|& //and// | //can operate on and return vectors, but// <span style="white-space: pre-wrap;">&&</span> //and// @</td>
<td>@@ <em>return scalars</em>##</td>
<td>and or not</td>
<td>@@&& </td>
<td> !@</td>
</tr>
<tr>
<td><a name="relational-op"></a><a href="#relational-op-note">relational operators</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>== ~= > < >= <=</td>
<td>== != > < >= <=</td>
<td>== != > < >= <=</td>
<td>== != > < >= <=</td>
</tr>
<tr>
<td><a name="int-type"></a><a href="#int-type-note">integer type</a></td>
<td> </td>
<td> </td>
<td><span style="color: gray"># Python:</span><br />
int<br />
<br />
<span style="color: gray"># NumPy:</span><br />
int8 int16 int32 int64</td>
<td>Int8 Int16 Int32 Int64 Int128<br />
<br />
Int <span style="color: gray"><em>is either 32 or 64 bits, depending on</em></span> WORD_SIZE</td>
</tr>
<tr>
<td><a name="unsigned-type"></a><a href="#unsigned-type-note">unsigned type</a></td>
<td> </td>
<td> </td>
<td>uint8 uint16 uint32 uint64</td>
<td>UInt8 UInt16 UInt32 UInt64 UInt128<br />
<br />
UInt <span style="color: gray"><em>is either 32 or 64 bits, depending on</em></span> WORD_SIZE</td>
</tr>
<tr>
<td><a name="float-type"></a><a href="#float-type-note">float type</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td> </td>
<td> </td>
<td><span style="color: gray"># Python:</span><br />
float<br />
<br />
<span style="color: gray"># NumPy:</span><br />
float16 float32 float64</td>
<td>Float16 Float32 Float64</td>
</tr>
<tr>
<td><a name="arith-op"></a><a href="#arith-op-note">arithmetic operators</a><br />
<span style="color: gray"><em>add, sub, mult, div, quot, rem</em></span></td>
<td>+ - * / <span style="color: gray"><em>none</em></span> mod(<span style="color: gray"><em>n</em></span>, <span style="color: gray"><em>divisor</em></span>)</td>
<td>+ - * / %/% %%</td>
<td>+ - * / // %</td>
<td>+ - * / div(<span style="color: gray"><em>n</em></span>, <span style="color: gray"><em>divisor</em></span>) rem(<span style="color: gray"><em>n</em></span>, <span style="color: gray"><em>divisor</em></span>)<br />
<br />
<span style="color: gray"># always non-negative:</span><br />
mod(<span style="color: gray"><em>n</em></span>, <span style="color: gray"><em>divisor</em></span>)</td>
</tr>
<tr>
<td><a name="int-div"></a><a href="#int-div-note">integer division</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>fix(13 / 5)</td>
<td>13 %/% 5<br />
as.integer(13 / 5)</td>
<td>13 // 5</td>
<td>div(13, 5)</td>
</tr>
<tr>
<td><a name="int-div-zero"></a><a href="#int-div-zero-note">integer division by zero</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>Inf NaN <span style="color: gray"><em>or</em></span> -Inf</td>
<td><span style="color: gray"><em>result of converting Inf or NaN to an integer with as.integer:</em></span><br />
NA</td>
<td><span style="color: gray"><em>raises</em> ZeroDivisionError</span></td>
<td><span style="color: gray"><em>raises</em> DivideError</span></td>
</tr>
<tr>
<td><a name="float-div"></a><a href="#float-div-note">float division</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>13 / 5</td>
<td>13 / 5</td>
<td>float(13) / 5</td>
<td>13 / 5<br />
5 \ 13</td>
</tr>
<tr>
<td><a name="float-div-zero"></a><a href="#float-div-zero-note">float division by zero</a><br />
<span style="color: gray"><em>dividend is positive, zero, negative</em></span></td>
<td><span style="color: gray"><em>these values are literals:</em></span><br />
Inf<br />
NaN<br />
-Inf</td>
<td><span style="color: gray"><em>these values are literals:</em></span><br />
Inf<br />
NaN<br />
-Inf</td>
<td><span style="color: gray"><em>raises</em> ZeroDivisionError</span></td>
<td><span style="color: gray"><em>these values are literals:</em></span><br />
Inf<br />
NaN<br />
-Inf</td>
</tr>
<tr>
<td><a name="power"></a><a href="#power-note">power</a></td>
<td>2 ^ 16</td>
<td>2 ^ 16<br />
2 ** 16</td>
<td>2 <span style="white-space: pre-wrap;">**</span> 16</td>
<td>2 ^ 16</td>
</tr>
<tr>
<td><a name="sqrt"></a><a href="#sqrt-note">sqrt</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>sqrt(2)</td>
<td>sqrt(2)</td>
<td>math.sqrt(2)</td>
<td>sqrt(2)</td>
</tr>
<tr>
<td><a name="sqrt-negative-one"></a><a href="#sqrt-negative-one-note">sqrt -1</a></td>
<td><span style="color: gray">% returns 0 + 1i:</span><br />
sqrt(-1)</td>
<td><span style="color: gray"># returns NaN:</span><br />
sqrt(-1)<br />
<br />
<span style="color: gray"># returns 0+1i:</span><br />
sqrt(-1+0i)</td>
<td><span style="color: gray"># raises ValueError:</span><br />
math.sqrt(-1)<br />
<br />
<span style="color: gray"># returns 1.41421j:</span><br />
import cmath<br />
cmath.sqrt(-1)</td>
<td><span style="color: gray"># raises DomainError:</span><br />
sqrt(-1)<br />
<br />
<span style="color: gray"># returns 0.0 + 1.0im:</span><br />
sqrt(-1 + 0im)</td>
</tr>
<tr>
<td><a name="transcendental-func"></a><a href="#transcendental-func-note">transcendental functions</a></td>
<td>exp log sin cos tan asin acos atan atan2</td>
<td>exp log sin cos tan asin acos atan atan2</td>
<td>math.exp math.log math.sin math.cos math.tan math.asin math.acos math.atan math.atan2</td>
<td>exp log sin cos tan asin acos atan atan2</td>
</tr>
<tr>
<td><a name="transcendental-const"></a><a href="#transcendental-const-note">transcendental constants</a></td>
<td>pi e</td>
<td>pi exp(1)</td>
<td>math.pi math.e</td>
<td>pi e</td>
</tr>
<tr>
<td><a name="float-truncation"></a><a href="#float-truncation-note">float truncation</a><br />
<span style="color: gray"><em>round towards zero, to nearest integer, down, up</em></span></td>
<td>fix(x)<br />
round(x)<br />
floor(x)<br />
ceil(x)</td>
<td>as.integer(x)<br />
round(x)<br />
floor(x)<br />
ceiling(x)</td>
<td>int(x)<br />
int(round(x))<br />
math.floor(x)<br />
math.ceil(x)</td>
<td>Int(trunc(x))<br />
Int(round(x))<br />
Int(floor(x))<br />
Int(ceil(x))<br />
<br />
<span style="color: gray"># trunc() and other functions return floats.<br />
# Int() raises InexactError if float argument has<br />
# nonzero fractional portion.</span></td>
</tr>
<tr>
<td><a name="absolute-val"></a><a href="#absolute-val-note">absolute value</a><br />
<span style="color: gray"><em>and signum</em></span></td>
<td>abs sign</td>
<td>abs sign</td>
<td>abs(-3.7)<br />
math.copysign(1, -3.7)</td>
<td>abs(-3.7)<br />
sign(-3.7)</td>
</tr>
<tr>
<td><a name="int-overflow"></a><a href="#int-overflow-note">integer overflow</a></td>
<td><span style="color: gray"><em>becomes float; largest representable integer in the variable</em> intmax</span></td>
<td><span style="color: gray"><em>becomes float; largest representable integer in the variable</em> .Machine$integer.max</span></td>
<td><span style="color: gray"><em>becomes arbitrary length integer of type</em> long</span></td>
<td> </td>
</tr>
<tr>
<td><a name="float-overflow"></a><a href="#float-overflow-note">float overflow</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>Inf</td>
<td>Inf</td>
<td><span style="color: gray"><em>raises</em> OverflowError</span></td>
<td> </td>
</tr>
<tr>
<td><a name="float-limits"></a><a href="#float-limits-note">float limits</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>eps<br />
realmax<br />
realmin</td>
<td>.Machine$double.eps<br />
.Machine$double.xmax<br />
.Machine$double.xmin</td>
<td>np.finfo(np.float64).eps<br />
np.finfo(np.float64).max<br />
np.finfo(np.float64).min</td>
<td> </td>
</tr>
<tr>
<td><a name="rational-construction"></a><a href="#rational-construction-note">rational construction</a></td>
<td> </td>
<td> </td>
<td> </td>
<td>22 <span style="white-space: pre-wrap;">//</span> 7</td>
</tr>
<tr>
<td><a name="rational-decomposition"></a><a href="#rational-decomposition-note">rational decomposition</a></td>
<td> </td>
<td> </td>
<td> </td>
<td>num(22 <span style="white-space: pre-wrap;">//</span> 7)<br />
den(22 <span style="white-space: pre-wrap;">//</span> 7)</td>
</tr>
<tr>
<td><a name="complex-types"></a><a href="#complex-types-note">complex types</a></td>
<td> </td>
<td> </td>
<td>complex64 complex128</td>
<td>Complex32 Complex64 Complex128</td>
</tr>
<tr>
<td><a name="complex-construction"></a><a href="#complex-construction-note">complex construction</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>1 + 3i</td>
<td>1 + 3i</td>
<td>1 + 3j</td>
<td>1 + 3im<br />
complex(1, 3)</td>
</tr>
<tr>
<td><a name="complex-decomposition"></a><a href="#complex-decomposition-note">complex decomposition</a></td>
<td>real imag<br />
abs arg<br />
conj</td>
<td>Re Im<br />
abs Arg<br />
Conj</td>
<td>import cmath<br />
<br />
z.real<br />
z.imag<br />
cmath.polar(z)[1]</td>
<td>real(1 + 3im)<br />
imag(1 + 3im)<br />
abs(1 + 3im)<br />
angle(1 + 3im)<br />
conj(1 + 3im)</td>
</tr>
<tr>
<td><a name="random-num"></a><a href="#random-num-note">random number</a><br />
<span style="color: gray"><em>uniform integer, uniform float</em></span></td>
<td>floor(100 * rand)<br />
rand</td>
<td>floor(100 * runif(1))<br />
runif(1)</td>
<td>np.random.randint(0, 100)<br />
np.random.rand()</td>
<td>rand(1:100)<br />
rand()</td>
</tr>
<tr>
<td><a name="random-seed"></a><a href="#random-seed-note">random seed</a><br />
<span style="color: gray"><em>set, get, and restore</em></span></td>
<td>rand('state', 17)<br />
sd = rand('state')<br />
rand('state', sd)</td>
<td>set.seed(17)<br />
sd = .Random.seed<br />
<span style="color: gray"><em>none</em></span></td>
<td>np.random.seed(17)<br />
sd = np.random.get_state()<br />
np.random.set_state(sd)</td>
<td> </td>
</tr>
<tr>
<td><a name="bit-op"></a><a href="#bit-op-note">bit operators</a></td>
<td>bitshift(100, 3)<br />
bitshift(100, -3)<br />
bitand(1, 2)<br />
bitor(1, 2)<br />
bitxor(1, 2)<br />
<span style="color: gray">% MATLAB:</span><br />
bitcmp(1, 'uint16')<br />
<span style="color: gray">% Octave:</span><br />
bitcmp(1, 16)</td>
<td><span style="color: gray"><em>none</em></span></td>
<td>100 <span style="white-space: pre-wrap;"><<</span> 3<br />
100 <span style="white-space: pre-wrap;">>></span> 3<br />
1 & 2<br />
1 | 2<br />
1 ^ 2<br />
~1</td>
<td> </td>
</tr>
<tr>
<td><a name="binary-octal-hex-literals"></a><a href="#binary-octal-hex-literals-note">binary, octal, and hex literals</a></td>
<td> </td>
<td> </td>
<td> </td>
<td>0b101010<br />
0o52<br />
0x2a</td>
</tr>
<tr>
<td><a name="radix"></a><a href="#radix-note">radix</a><br />
<span style="color: gray"><em>convert integer to and from string with radix</em></span></td>
<td> </td>
<td> </td>
<td> </td>
<td>base(7, 42)<br />
parse(Int, "60", 7)</td>
</tr>
<tr>
<th colspan="5"><a name="strings"></a><a href="#strings-note">strings</a></th>
</tr>
<tr>
<th></th>
<th><a href="#matlab">matlab</a></th>
<th><a href="#r">r</a></th>
<th><a href="#numpy">numpy</a></th>
<th><a href="#julia">julia</a></th>
</tr>
<tr>
<td><a name="str-literal"></a><a href="#str-literal-note">literal</a></td>
<td> 'don''t say "no"'<br />
<br />
<span style="color: gray">% Octave only:</span><br />
"don't say \"no\""</td>
<td>"don't say \"no\""<br />
'don\'t say "no"'</td>
<td>'don\'t say "no"'<br />
"don't say \"no\""<br />
r"don't " r'say "no"'</td>
<td>"don't say \"no\""</td>
</tr>
<tr>
<td><a name="str-newline"></a><a href="#str-newline-note">newline in literal</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td><span style="color: gray"><em>no</em></span></td>
<td><span style="color: gray"><em>yes</em></span></td>
<td><span style="color: gray"><em>no</em></span></td>
<td><span style="color: gray"><em>yes</em></span></td>
</tr>
<tr>
<td><a name="str-esc"></a><a href="#str-esc-note">literal escapes</a></td>
<td><span style="color: gray">% Octave double quote only:</span><br />
\\ \" \' \0 \a \b \f \n \r \t \v</td>
<td>\\ \" \' \a \b \f \n \r \t \v \<span style="color: gray"><em>ooo</em></span></td>
<td><span style="color: gray"># single and double quoted:</span><br />
\<span style="color: gray"><em>newline</em></span> \\ \' \" \a \b \f \n \r \t \v \<span style="color: gray"><em>ooo</em></span> \x<span style="color: gray"><em>hh</em></span></td>
<td>\\ \" \' \a \b \f \n \t \r \v<br />
\<span style="color: gray"><em>ooo</em></span> \x<span style="color: gray"><em>hh</em></span> \u<span style="color: gray"><em>hhhh</em></span> \U<span style="color: gray"><em>hhhhhhhh</em></span></td>
</tr>
<tr>
<td><a name="var-interpolation"></a><a href="#var-interpolation-note">variable interpolation</a></td>
<td> </td>
<td> </td>
<td> </td>
<td>count = 3<br />
item = "ball"<br />
println("$count $(item)s")</td>
</tr>
<tr>
<td><a name="expr-interpolation"></a><a href="#expr-interpolation-note">expression interpolation</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td> </td>
<td> </td>
<td> </td>
<td>"1 + 1 = $(1 + 1)"</td>
</tr>
<tr>
<td><a name="str-concat"></a><a href="#str-concat-note">concatenate</a></td>
<td>strcat('one ', 'two ', 'three')</td>
<td>paste("one", "two", "three", sep=" ")</td>
<td>'one ' + 'two ' + 'three'<br />
<span style="color: gray"><em>literals, but not variables, can be concatenated with juxtaposition:</em></span><br />
'one ' "two " 'three'</td>
<td>"one " * "two " * "three"<br />
<br />
string("one ", "two ", "three")</td>
</tr>
<tr>
<td><a name="str-replicate"></a><a href="#str-replicate-note">replicate</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>hbar = repmat('-', 1, 80)</td>
<td>hbar = paste(rep('-', 80), collapse='')</td>
<td>hbar = '-' * 80</td>
<td>hbar = "-" ^ 80<br />
<br />
hbar = repeat("-", 80)</td>
</tr>
<tr>
<td><a name="index-substr"></a><a href="#index-substr-note">index of substring</a></td>
<td><span style="color: gray">% returns array of one-indexed<br />
% locations </span><br />
strfind('hello', 'el')</td>
<td><span style="color: gray"><em>counts from one, returns<br />
-1 if not found</em></span><br />
regexpr("el", "hello")</td>
<td><span style="color: gray"># Counts from zero; raises ValueError if not found:</span><br />
'hello'.index('el')</td>
<td><span style="color: gray"># returns UnitRange:</span><br />
search("hello", "el")</td>
</tr>
<tr>
<td><a name="extract-substr"></a><a href="#extract-substr-note">extract substring</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>s = 'hello'<br />
<span style="color: gray">% syntax error: 'hello'(1:4)</span><br />
s(1:4)</td>
<td>substr("hello", 1, 4)</td>
<td>'hello'[0:4]</td>
<td>"hello"[1:4]</td>
</tr>
<tr>
<td><a name="split"></a><a href="#split-note">split</a></td>
<td> <span style="color: gray">% returns cell array:</span><br />
strsplit('foo,bar,baz', ',')</td>
<td>strsplit('foo,bar,baz', ',')</td>
<td>'foo,bar,baz'.split(',')</td>
<td>split("foo,bar,baz", ",")</td>
</tr>
<tr>
<td><a name="join"></a><a href="#join-note">join</a></td>
<td><span style="color: gray">% takes cell array as arg:</span><br />
strjoin({'foo', 'bar', 'baz'}, ',')</td>
<td>paste("foo", "bar", "baz", sep=",")<br />
paste(c('foo', 'bar', 'baz'),<br />
<span style="white-space: pre-wrap;"> </span>collapse=',')</td>
<td>','.join(['foo', 'bar', 'baz'])</td>
<td>join(["foo", "bar", "baz"], ",")</td>
</tr>
<tr>
<td><a name="trim"></a><a href="#trim-note">trim</a><br />
<span style="color: gray"><em>both sides, left, right</em></span></td>
<td>strtrim(' foo ')<br />
<span style="color: gray"><em>none</em></span><br />
deblank('foo ')</td>
<td>gsub("(^[\n\t ]+|[\n\t ]+$)",<br />
<span style="white-space: pre-wrap;"> </span>"",<br />
<span style="white-space: pre-wrap;"> </span>" foo ")<br />
sub("^[\n\t ]+", "", " foo")<br />
sub("[\n\t ]+$", "", "foo ")</td>
<td>' foo '.strip()<br />
' foo'.lstrip()<br />
'foo '.rstrip()</td>
<td> </td>
</tr>
<tr>
<td><a name="pad"></a><a href="#pad-note">pad</a><br />
<span style="color: gray"><em>on right, on left, centered</em></span></td>
<td>s = repmat(' ', 1, 10)<br />
s(1:5) = 'lorem'<br />
strjust(s, 'left')<br />
strjust(s, 'right')<br />
strjust(s, 'center')</td>
<td>sprintf("%-10s", "lorem")<br />
sprintf("%10s", "lorem")<br />
<span style="color: gray"><em>none</em></span></td>
<td>'lorem'.ljust(10)<br />
'lorem'.rjust(10)<br />
'lorem'.center(10)</td>
<td> </td>
</tr>
<tr>
<td><a name="num-to-str"></a><a href="#num-to-str-note">number to string</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>strcat('value: ', num2str(8))</td>
<td>paste("value: ", toString("8"))</td>
<td>'value: ' + str(8)</td>
<td> </td>
</tr>
<tr>
<td><a name="str-to-num"></a><a href="#str-to-num-note">string to number</a></td>
<td>7 + str2num('12')<br />
73.9 + str2num('.037')</td>
<td>7 + as.integer("12")<br />
73.9 + as.double(".037")</td>
<td>7 + int('12')<br />
73.9 + float('.037')</td>
<td>7 + parse(Int, "12")<br />
73.9 + parse(Float64, ".037")</td>
</tr>
<tr>
<td><a name="case-manipulation"></a><a href="#case-manipulation-note">translate case</a></td>
<td>lower('FOO')<br />
upper('foo')</td>
<td>tolower("FOO")<br />
toupper("foo")</td>
<td>'foo'.upper()<br />
'FOO'.lower()</td>
<td>uppercase("foo")<br />
lowercase("FOO")</td>
</tr>
<tr>
<td><a name="sprintf"></a><a href="#sprintf-note">sprintf</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>sprintf('%s: %.3f %d', 'foo', 2.2, 7)</td>
<td>sprintf("%s: %.3f %d", "foo", 2.2, 7)</td>
<td>'%s: %.3f %d' % ('foo', 2.2, 7)</td>
<td>@sprintf("%s: %.2f %d", "foo", 2.2, 7)</td>
</tr>
<tr>
<td><a name="str-len"></a><a href="#str-len-note">length</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>length('hello')</td>
<td>nchar("hello")</td>
<td>len('hello')</td>
<td>length("hello")<br />
<br />
<span style="color: gray"># index of first byte of last char:</span><br />
endof("hello")</td>
</tr>
<tr>
<td><a name="char-access"></a><a href="#char-access-note">character access</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>s = 'hello'<br />
<span style="color: gray">% syntax error: 'hello'(1)</span><br />
s(1)</td>
<td>substr("hello", 1, 1)</td>
<td>'hello'[0]</td>
<td>"hello"[1]<br />
<br />
<span style="color: gray"># index must be byte-index of the first byte of a<br />
# character. Raises BoundsErrror if no such byte,<br />
# and UnicodeError if byte not first in char.</span></td>
</tr>
<tr>
<td><a name="chr-ord"></a><a href="#chr-ord-note">chr and ord</a></td>
<td>char(65)<br />
double('A')</td>
<td>intToUtf8(65)<br />
utf8ToInt("A")</td>
<td>chr(65)<br />
ord('A')</td>
<td>Char(65)<br />
Int('A')</td>
</tr>
<tr>
<th colspan="5"><a name="regexes"></a><a href="#regexes-note">regular expressions</a></th>
</tr>
<tr>
<th></th>
<th><a href="#matlab">matlab</a></th>
<th><a href="#r">r</a></th>
<th><a href="#numpy">numpy</a></th>
<th><a href="#julia">julia</a></th>
</tr>
<tr>
<td><a name="char-class-abbrevs"></a><a href="#char-class-abbrevs-note">character class abbreviations</a></td>
<td>. \d \D \s \S \w \W<br />
<br />
<span style="color: gray">% also C-string style backslash escapes:</span><br />
\a \b \f \n \r \t \v</td>
<td><span style="color: gray"># escape backslash in strings by doubling:</span><br />
. \d \D \s \S \w \W</td>
<td>. \d \D \s \S \w \W</td>
<td>. \d \D \h \H \s \S \v \V \w \W</td>
</tr>
<tr>
<td><a name="regex-anchors"></a><a href="#regex-anchors-note">anchors</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>^ $ \< \</td>
<td><span style="color: gray"># escape backslash in strings by doubling:</span><br />
^ $ \< \> \b \B</td>
<td>^ $ \A \b \B \Z</td>
<td>^ $ \A \b \B \z \Z</td>
</tr>
<tr>
<td><a name="regex-match"></a><a href="#regex-match-note">match test</a></td>
<td>regexp('hello', '^[a-z]+$')<br />
regexp('hello', '^\S+$')</td>
<td>regexpr("^[a-z]+$", "hello") > 0<br />
regexpr('^\\S+$', "hello") > 0</td>
<td>re.search(r'^[a-z]+$', 'hello')<br />
re.search(r'^\S+$', 'hello')</td>
<td>ismatch(r"^[a-z]+$", "hello")</td>
</tr>
<tr>
<td><a name="case-insensitive-regex-match"></a><a href="#case-insensitive-regex-match-note">case insensitive match test</a></td>
<td>regexpi('Lorem Ipsum', 'lorem')</td>
<td>regexpr('(?i)lorem', "Lorem Ipsum") > 0</td>
<td>re.search(r'lorem', 'Lorem Ipsum', re.I)</td>
<td>ismatch(r"lorem"i, "Lorem Ipsum")</td>
</tr>
<tr>
<td><a name="regex-modifiers"></a><a href="#regex-modifiers-note">modifiers</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td><span style="color: gray"><em>none</em></span></td>
<td>(?i) (?m) (?s) (?x)</td>
<td>re.I re.M re.S re.X</td>
<td>i m s x</td>
</tr>
<tr>
<td><a name="regex-subst"></a><a href="#regex-subst-note">substitution</a><br />
<span style="color: gray"><em>first match, all matches</em></span></td>
<td>s = 'do re mi mi mi'<br />
regexprep(s, 'ma', 'once')<br />
regexprep(s, 'mi', 'ma')</td>
<td>sub('mi', 'ma', 'do re mi mi mi')<br />
gsub('mi', 'ma', 'do re mi mi mi')</td>
<td>rx = re.compile(r'mi')<br />
s = rx.sub('ma', 'do re mi mi mi', 1)<br />
s2 = rx.sub('ma', 'do re mi mi mi')</td>
<td>replace("do re mi mi mi", r"mi", s"ma", 1)<br />
replace("do re mi mi mi", r"mi", s"ma")</td>
</tr>
<tr>
<td><a name="regex-backreference"></a><a href="#regex-backreference-note">backreference in match and substitution</a></td>
<td>regexp('do do', '(\w+) \1')<br />
regexprep('do re', '(\w+) (\w+)', '$2 $1')</td>
<td>regexpr('(\\w+) \\1', 'do do') > 0<br />
sub('(\\w+) (\\w+)', '\\2 \\1', 'do re')</td>
<td><span style="color: gray"><em>none</em></span><br />
<br />
rx = re.compile(r'(\w+) (\w+)')<br />
rx.sub(r'\2 \1', 'do re')</td>
<td>ismatch(r"(\w+) \1", "do do")</td>
</tr>
<tr>
<td><a name="group-capture"></a><a href="#group-capture-note">group capture</a></td>
<td> </td>
<td> </td>
<td>rx = '(\d{4})-(\d{2})-(\d{2})'<br />
m = re.search(rx, '2010-06-03')<br />
yr, mo, dy = m.groups()</td>
<td>rx = r"(\d{4})-(\d{2})-(\d{2})"<br />
m = match(rx, "2010-06-03")<br />
yr, mn, dy = m.captures</td>
</tr>
<tr>
<th colspan="5"><a name="dates-time"></a><a href="#dates-time-note">dates and time</a></th>
</tr>
<tr>
<th></th>
<th><a href="#matlab">matlab</a></th>
<th><a href="#r">r</a></th>
<th><a href="#numpy">numpy</a></th>
<th><a href="#julia">julia</a></th>
</tr>
<tr>
<td><a name="current-date-time"></a><a href="#current-date-time-note">current date/time</a><br />
<span style="white-space: pre-wrap;"> </span></td>
<td>t = now</td>
<td>t = as.POSIXlt(Sys.time())</td>
<td>import datetime<br />
<br />
t = datetime.datetime.now()</td>
<td>t = now()</td>
</tr>
<tr>
<td><a name="date-time-type"></a><a href="#date-time-type-note">date/time type</a></td>
<td><span style="color: gray"><em>floating point number representing days since year 0 in the Gregorian calendar</em></span></td>
<td>POSIXlt</td>
<td>datettime</td>
<td>DateTime</td>
</tr>
<tr>
<td><a name="date-time-diff-type"></a><a href="#date-time-diff-type-note">date/time difference type</a></td>
<td><span style="color: gray"><em>floating point number representing days</em></span></td>
<td><span style="color: gray"><em>a</em> difftime <em>object which behaves like a floating point number representing seconds</em></span></td>
<td><span style="color: gray">timedelta, <em>which can be converted to float value in seconds via</em> total_seconds() <em>method</em></span></td>
<td>Base.Dates.Millisecond</td>
</tr>
<tr>
<td><a name="date-parts"></a><a href="#date-parts-note">get date parts</a></td>
<td>dv = datevec(t)<br />
dv(1)<br />
dv(2)<br />
dv(3)<br />
<span style="color: gray">% syntax error: datevec(t)(1)</span></td>
<td>t$year + 1900<br />
t$mon + 1<br />
t$mday</td>
<td>t.year<br />
t.month<br />
t.day</td>