Sorting lists within a list in Python

Question

I have a list J consisting of lists. I am trying to sort elements of each list in ascending order. I present the current and expected outputs.

J=[[10, 4, 7], [10, 4],[1,9,8]]
for i in range(0,len(J)):
    J[0].sort()

The current output is

[[4, 7, 10], [10, 4], [1, 9, 8]]

The expected output is

[[4, 7, 10], [4, 10], [1, 8, 9]]

Close, but try: J[i].sort() inside the loop rather than J[0].sort(). — DarrylG
– DarrylG, Commented Jul 31, 2022 at 8:47
Use the object directly in the loop to avoid this confusion: for li in J: li.sort() — DeepSpace
– DeepSpace, Commented Jul 31, 2022 at 8:49
Try, either [sorted(l) for l in J] or [l for l in J if l.sort() is None]. Check the following URL for more details: docs.python.org/3/howto/sorting.html — ravi
– ravi, Commented Jul 31, 2022 at 8:57
@RaviJoshi The second example is very non-idiomatic and confusing. List comprehensions should not be abused for a side effect — DeepSpace
– DeepSpace, Commented Jul 31, 2022 at 9:31

Erastus Nzula · Accepted Answer · 2022-07-31 09:13:35Z

1

Just remove the range

J=[[10, 4, 7], [10, 4],[1,9,8]]
for i in J:
    i.sort()
print(J)

Output:

[[4, 7, 10], [4, 10], [1, 8, 9]]

answered Jul 31, 2022 at 9:13

Erastus Nzula

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