CODEWITHSUNDEEP
pythonalgorithmsorting
Thandor7765
Thandor7765

Reputation: 53

What is wrong with this sorting code? Python

So i'm supposed to take in a number n, add n numbers to a list, then sort the list and print.

numCol=int(input());
vals=[];
for x in range(numCol):
    vals.append(int(input()))

for x in range(len(vals)):
    curr=vals[x];
    for y in range(x+1,len(vals)):
        if(curr>vals[y]):
            temp=vals[y];
            vals[y]=curr;
            vals[x]=temp;
print(vals);

the code doesn't work properly. We haven't learned sorting algorithms thoroughly really yet, so i'm kinda just making my own, but it resembles selection sort I think. Anyways, why is it not printing the values in ascending order?

Edit: I input 4, then make list 4, 3, 2, 1. Output is [1, 4, 4, 4]

Upvotes: 0

Views: 91

Answers (4)

lightsong
lightsong

Reputation: 391

You're welcome - 

numCol=int(input());
vals=[];
for x in range(numCol):
    vals.append(int(input()))

for x in range(len(vals)):
    for y in range(x+1,len(vals)):
    if(vals[x]>vals[y]):
        temp=vals[y]
        vals[y]=vals[x]
        vals[x]=temp
print(vals)

The problem was that you weren't changing the value of cur to be compared correctly.

Edit - Just saw other answers had beat me to it :(

Upvotes: 0

Samvel Petrosov
Samvel Petrosov

Reputation: 7706

Change this part of code 

 for x in range(len(vals)):
    curr=vals[x];
    for y in range(x+1,len(vals)):
        if(curr>vals[y]):
            temp=vals[y];
            vals[y]=curr;
            vals[x]=temp;

To this:

for x in range(len(vals)):
    for y in range(x+1,len(vals)):
        if(vals[x]>vals[y]):
            temp=vals[y];
            vals[y]=vals[x];
            vals[x]=temp;

Upvotes: 1

tfv
tfv

Reputation: 6259

You can solve sorting of lists much easier and in a more pythonic way, simply use the sort command, here is an example:

import random

a=random.sample(range(30), 10)
print a
a.sort()
print a

Upvotes: 0

delta
delta

Reputation: 3818

the problem is curr should change after swap.

for x in range(len(vals)):
    curr=vals[x];
    for y in range(x+1,len(vals)):
        if(curr > vals[y]):
            temp = vals[y]
            vals[y] = curr
            vals[x] = temp
            curr = vals[x] # <--

Upvotes: 1

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