Added 3 new sorting algorithms in python

Sorting/Iterative_Merge_Sort.py

@@ -0,0 +1,35 @@
+def merge(left, right): 
+    if not len(left) or not len(right): 
+        return left or right 
+
+    result = [] 
+    i, j = 0, 0
+    while (len(result) < len(left) + len(right)): 
+        if left[i] < right[j]: 
+            result.append(left[i]) 
+            i+= 1
+        else: 
+            result.append(right[j]) 
+            j+= 1
+        if i == len(left) or j == len(right): 
+            result.extend(left[i:] or right[j:]) 
+            break 
+
+    return result 
+
+def mergesort(list): 
+    if len(list) < 2: 
+        return list
+
+    middle = len(list)/2
+    left = mergesort(list[:middle]) 
+    right = mergesort(list[middle:]) 
+
+    return merge(left, right) 
+
+seq = [12, 11, 13, 5, 6, 7] 
+print("Given array is") 
+print(seq);  
+print("\n") 
+print("Sorted array is") 
+print(mergesort(seq)) 

Sorting/Selection_Sort.py

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+# Python program for implementation of Selection 
+# Sort 
+import sys 
+A = [64, 25, 12, 22, 11] 
+
+# Traverse through all array elements 
+for i in range(len(A)): 
+
+    # Find the minimum element in remaining  
+    # unsorted array 
+    min_idx = i 
+    for j in range(i+1, len(A)): 
+        if A[min_idx] > A[j]: 
+            min_idx = j 
+
+    # Swap the found minimum element with  
+    # the first element         
+    A[i], A[min_idx] = A[min_idx], A[i] 
+
+# Driver code to test above 
+print ("Sorted array") 
+for i in range(len(A)): 
+    print("%d" %A[i]),  

Sorting/radix_sort.py

@@ -0,0 +1,64 @@
+# Python program for implementation of Radix Sort
+# A function to do counting sort of arr[] according to
+# the digit represented by exp.
+
+def countingSort(arr, exp1):
+
+    n = len(arr)
+
+    # The output array elements that will have sorted arr
+    output = [0] * (n)
+
+    # initialize count array as 0
+    count = [0] * (10)
+
+    # Store count of occurrences in count[]
+    for i in range(0, n):
+        index = (arr[i] / exp1)
+        count[int(index % 10)] += 1
+
+    # Change count[i] so that count[i] now contains actual
+    # position of this digit in output array
+    for i in range(1, 10):
+        count[i] += count[i - 1]
+
+    # Build the output array
+    i = n - 1
+    while i >= 0:
+        index = (arr[i] / exp1)
+        output[count[int(index % 10)] - 1] = arr[i]
+        count[int(index % 10)] -= 1
+        i -= 1
+
+    # Copying the output array to arr[],
+    # so that arr now contains sorted numbers
+    i = 0
+    for i in range(0, len(arr)):
+        arr[i] = output[i]
+
+# Method to do Radix Sort
+def radixSort(arr):
+
+    # Find the maximum number to know number of digits
+    max1 = max(arr)
+
+    # Do counting sort for every digit. Note that instead
+    # of passing digit number, exp is passed. exp is 10^i
+    # where i is current digit number
+    exp = 1
+    while max1 / exp > 0:
+        countingSort(arr, exp)
+        exp *= 10
+
+
+# Driver code
+arr = [170, 45, 75, 90, 802, 24, 2, 66]
+
+# Function Call
+radixSort(arr)
+
+for i in range(len(arr)):
+    print(arr[i])
+
+# This code is contributed by Mohit Kumra
+# Edited by Patrick Gallagher