binarySearch.py

#!/usr/bin/python
# Python 2.7.6
# Authors: [thel3l, lunaroyster]

def binarySearch(sortedList, item, start=None, end=None):
    #This happens when the item is not present in the array
    if(start>end):
        return(False)
    
    #If start and end aren't defined, assume it's the entire array    
    if(start==None):
        start = 0
    if(end==None):
        end = len(sortedList)-1
    
    #Calc midpoint
    midpoint = (start+end)/2
    
    if(item == sortedList[midpoint]):
        # We've found what we want
        return(midpoint)
    elif(item > sortedList[midpoint]):
        # The item is greater than where we are. It must be in the second half of the array.
        return(binarySearch(sortedList, item, midpoint+1, end))
    elif(item < sortedList[midpoint]):
        # The item is smaller than where we are. It must be in the first half of the array.
        return(binarySearch(sortedList, item, start, midpoint-1))

# Test integers
ints = [1,2,3,4,5,6,7,8,9,10]
print(binarySearch(sortedList=ints, item=5))

# Test strings
strings = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k"]
print(binarySearch(sortedList=strings, item="i"))

# Test floats
floats = [3.4, 4.1, 8.3, 9.4, 10.1, 12.8, 14.9, 15.1, 19.8, 21.7]
print(binarySearch(sortedList=floats, item=15.1))