Question

I tried to sort using sorted

dir =["A1","A2","A10","A3"]
sorted(dir)

My expected array is

["A1","A2","A3","A10"]

but actual result is

["A1", "A10", "A2", "A3"]

How to sort array by name in python ?

Answer 1

It is sorting by alphabetical order, so you need to break up the numbers and convert them to ints and sort with that. (Numbers in strings are treated as just characters, so it “sees” “A10” and tries to sort it first by “A”, then by “1”, and then by “0.”) For example:

>>> sorted(dir, key=lambda x: int(x[1:]))
['A1', 'A2', 'A3', 'A10']

If you are going to have other letters besides “A” in dir, you’ll need a more complicated sorting method, but it will be something along the same lines. (If you explain what dir contains more, I can write an example for that.) As mgilson’s comment points out, if the elements of dir follow the 1 char + number format, then you could take advantage of tuple sorting and do something like this:

>>> dir.append('B12')
>>> sorted(dir, key=lambda x: (x[0],int(x[1:])))
['A1', 'A2', 'A3', 'A10', 'B12']