Selection sort program python

Question

So this is supposed to be a sorting program, but for some reason, it is not sorting the file I\'m giving, but just giving me straight numbers as it is. Any help would be appreci

Answer 1

You have simply defined a method. You need to call it from somewhere. I added to your code and tested it. It works. Here you go: The last two lines actually make a call to the code you created: (be careful about indentation)

alist = [42,54,2,45,6,125,32]
print(alist)

def selectionSort(alist):
    for index in range(0, len(alist)):
        ismall = index
        for i in range(index,len(alist)):
            if alist[ismall] > alist[i]:
                ismall = i
        alist[index], alist[ismall] = alist[ismall], alist[index]
    return alist

newList = selectionSort(alist)
print newList

Answer 2

You didn't call the function!

def selectionSort(alist):
    for index in range(0, len(alist)):
        ismall = index
        for i in range(index,len(alist)):
            if alist[ismall] > alist[i]:
                ismall = i
        alist[index], alist[ismall] = alist[ismall], alist[index]

filename=input('Enter file path:')
file = open(filename, 'r')
alist = file.readlines()

# Call the function!
selectionSort(alist)
print(alist)

You've told Python what selectionSort means, but you haven't told it to sort anything. You need to call selectionSort(alist) to actually perform the sort.

Also, the order you want the list to be sorted in is most likely not the order you're telling Python to sort it in. alist is a list of strings, so you're telling Python to use lexicographic comparison to order the list. If it's supposed to be treated as, say, integers, you need to convert the data to integers:

alist = [int(line) for line in file]

(Also, since selectionSort modifies the list it operates on, it's best not to return the list. If you return it, it gives the impression that it creates a new, sorted list.)