Pythoncode_all.txt

#notes
#if statement

a = 12
if a < 21:
    print("not allowed")
else:
    print("allowed")


#elif statement

name = "kp"
if name is "pj":
    print("Hi")
elif name is "kj":
    print("morning")
elif name is "gh":
    print ("evening")
else:
    print("nothing matches")

# how to loop through for statement


foods = ["apple","banana","grapes","cucumber","corn"]

for f in foods:
    print(f)
    print(len(f))

foods = ["apple","banana","grapes","cucumber","corn"]

for f in foods[:2]:
    print(f)
    print(len(f))

# range and while loop

#create for loop without list

for x in range(10):
    print(x)

for x in range(1,11):
    print(x)


for x in range(1,11,2):
    print(x)

for x in range(2,11,2):
    print(x)
a = 5
while a < 1:
     print (a)
a += 1

#for infinite while loop stop process shortcut ctrl f2

# comment block three  single quotes

'''
for n in range(101):
    if n is magicnumber:
        print("found the magicnumber")
        break
    else:
        print(n)
'''

print ("magicnumber" +str(9))


# make a program to find out number divisible by 4 in 1 to 100


for i in range(101):
    if i % 4 is 0:
        print ("divisible number by 4 is " ,i)
    else:
        print()

# continue if condition become true it just doesnt print very nexl line and iterate again if condition false that print next line.
# Unlike break it doesn't come out from the loop it just come out from loop without printing or executing very next
#line of code and loops over again

numberstaken =[2,5,13,14,18]

print("here are the numbers that are still available")

for n in range(1,20):
    if n in numberstaken:
        continue
    print(n)

#same code with if else

for i in range(1,20):
    if i in numberstaken:
        print()
    else:
        print(i)


# functions

#defining function
def abc():
# logic of function
    print("functions are cool")
# calling function
abc()

def bitcoin_to_usd(btc):
    amount = btc * 527
    print (amount)

bitcoin_to_usd(3)

# Return values
# instead of printing storing values into variable by using return statement 

def allowed_voting_age (my_age):
    age = my_age/2 + 7
    return age
age_limit = allowed_voting_age(34)
age_limit_other = allowed_voting_age(48)
print("who can vote:",age_limit,"or older age")
print("who can vote:",age_limit_other,"or older age")

# default values for arguments Aanlyze again???

def get_gender(gender):
    if gender is 'm':
        gender = "male"
    elif gender is 'f':
        gender = "female"
    else:
     print(gender)


get_gender("m")

# variable scope


a = 2333

def corn():
    print(a)

def fudge():
    print(a)

corn()
fudge()

#ERROR

def corn():
    a = 2333
    print(a)

def fudge():
    print(a)

corn()
fudge()

#diiferent scope for same variable

def corn():
    a = 2333
    print(a)

def fudge():
    a =56
    print(a)

corn()
fudge()

#keyword arguments

def abc(name ="kp",number = 123,item = "kite"):
    print(name,number,item)
abc(name = "",item = "mgfk")

#function which can take flexible number of arguments

def add_numbers(*args):
    total = 0
    for a in args:
        total += a
    print(total)

add_numbers(2)
add_numbers(2,4,6,7)
add_numbers(36,78,23,45,79,90)

#another example

def health_calculator(age,apples_ate,cigs_smoked):
    answer = (100-age) + apples_ate * 3.5 - (cigs_smoked *2)
    print(answer)

data = [27,20,55]

health_calculator(data[0],data[1],data[2])
# shortcut way to get answer
health_calculator(*data)

# sets  is collection of item without duplicate

groceries = {'milk','almond','juice','yoghurt','milk','juice'}

print(groceries)

# dictionary

classmates = {'don': ' cool guy','gary' : ' too much funny','aska' : ' strange but nice'}

print(classmates['don'])

for k,v in classmates.items():
    print(k ,v)

# modules are other files which we just use in our program
# scenario : we are using function from file pycharm2.py in current program

import pycharm2

pycharm2.abc()

# another example

import random

x = random.randrange(1,1000)
print(x)

#to install other modules go to settings/project interpreter and click on + sign and install
# if you dont want that module click - sign and delete it

#download an image from the web

import random
import urllib.request

def download_web_image(url):
    random_number = random.randrange(1,1000)
    full_name = str(random_number) + ".jpg"
    urllib.request.urlretrieve(url,full_name)

# error because of firewall and all but this is how we download an image from internet

download_web_image("https://www.gstatic.com/webp/gallery/4.sm.jpg")

#solution and troubleshoot

1)google for the same error look for answers.
2)look all errors from last to first sequencially.
3)error was related to handshake ans ssl certificate.so pycharm client has not proper ssl certificate.we have to provide it.
4)in internet browser by copying weblink of image ,we will get an idea that it is working fine.so that means it has all ssl certificates.
5)what we need to do in this case is download this certificate and point out pycharm to that.
6)how to download that certificate:go to that image in browser --go to more  tools -- developer tools --security -- view certificate--details--here you can also make sure your content is coming from trusted source.--details -- copy to file -- save it somewhere in system--so now we have necessary ssl certificate.
7)now go to pycharm and go to files--settings--serch for python console--environment --environment variables-- give name as REQUESTS_CA_BUNDLE--value is the full path of downloaded ssl certificate--click ok --ok
8)now try to run again it should work 


# how to write in files

# make that file
fw = open('sample1.txt','w')
# write in this file
fw.write('writing in text file\n')
fw.write('I like writing\n')s

# close this file after done to save resources
fw.close()


# this is the location where it by default make a text file ,if you want to make it somewhere else just specify full path.

C:\Users\Pankaj\PycharmProjects\PythonPycharm1\sample.txt

# how to read from files

fr = open('sample.txt','r')
text = fr.read()
print(text)
fr.close()

'''The syntax to open a file object in Python is: 

file_object  = open(“filename”, “mode”) where file_object is the variable to add the file object. 
The second argument you see – mode – tells the interpreter and developer which way the file will be used.
Mode

Including a mode argument is optional because a default value of ‘r’ will be assumed if it is omitted. The ‘r’ value stands for read mode, which is just one of many. 

The modes are: 

‘r’ – Read mode which is used when the file is only being read 
‘w’ – Write mode which is used to edit and write new information to the file (any existing files with the same name will be erased when this mode is activated) 
‘a’ – Appending mode, which is used to add new data to the end of the file; that is new information is automatically amended to the end 
‘r+’ – Special read and write mode, which is used to handle both actions when working with a file
'''
# downloading files from web

from urllib import request

google_url = 'https://catalog.data.gov/dataset/american-factfinder-ii'


def download_data(csv_url):

    response = request.urlopen(csv_url)
    csv = response.read()
    csv_str = str(csv)
    lines = csv_str.split("\\n")
    dest_url = r'goog.csv'
    fx = open(dest_url,"w")
    for line in lines:
        fx.write(line + "\n")
    fx.close()

download_data(google_url)

#WEB CROWLER

import requests
from bs4 import BeautifulSoup

def trade_spider(max_pages):
    page = 1
    while page <= max_pages:
        url = 'http://www.coloring.ws/coloring.html'+ str(page)
        print (1)
        source_code = requests.get(url)
        print (2)
        soup = BeautifulSoup(source_code.text,'html.parser')
        print (3)
        for link in soup.findAll('img'):
            print (4)
            href = link.get('src')
            print(href)
           
            
        page += 1

trade_spider(5)