CODEWITHSUNDEEP
pythonsortinginsertion-sort
user4837997
user4837997

Reputation:

Insertion Sort Code in Python not sorting correctly

infile = open("array.txt", "r")
array = infile.readlines()
for i in range(len(array)):
    array[i] = str(array[i])
    array[i] = array[i].rstrip('\n')

#insertion sort
i = 0
while i <= (len(array) - 2):
    if array[i] > array[i+1]:
        temp = array[i+1]
        j = i
        while j >= 0 and array[j] > temp:
            array[j+1] = array[j]
            j = j - 1
        array[j+1] = temp
    i = i+1
print(array)

Some numbers are sorted correctly... while some numbers are not:

original list: ['1534', '78675', '2345', '7861', '345', '8761', '1', '27456']

['1534', '2345', '78675', '7861', '345', '8761', '1', '27456']
['1534', '2345', '7861', '78675', '345', '8761', '1', '27456']
['1534', '2345', '345', '7861', '78675', '8761', '1', '27456']
['1', '1534', '2345', '345', '7861', '78675', '8761', '27456']
['1', '1534', '2345', '27456', '345', '7861', '78675', '8761']
['1', '1534', '2345', '27456', '345', '7861', '78675', '8761']

The first 2 passes worked correctly, but in the 3rd pass, '345' wasn't sorted correctly. Can anyone help me?

EDIT: If I didn't read an array from a text file, and instead just defined array, the sorting worked. Why is this so?

Upvotes: 1

Views: 216

Answers (1)

Kevin
Kevin

Reputation: 76254

This is probably because "345" > "2345" is True, because the string "345" comes lexicographically after "2345". If you want numeric sorting, try filling your original list with numbers instead of strings.

array = [1534, 78675, 2345, 7861, 345, 8761, 1, 27456]
i = 0
while i <= (len(array) - 2):
    #etc

Result:

[1, 345, 1534, 2345, 7861, 8761, 27456, 78675]

Upvotes: 1

Related Questions