Sorting strings in Python with numbers somewhere in the middle-CodePudding

I want to find a way to sort strings that have numbers in them by their numerical size.

I found one way to sort strings that contain only numbers, which works well (Sorting numbers in string format with Python) but not when the string is a mix of words and numbers.

In this example I am creating the list in the order that I want, but the sorted() ruins it.

>>> s = ['A_10x05', 'A_10x50', 'A_10x100']
>>> print(sorted(s))
['A_10x05', 'A_10x100', 'A_10x50']

I am thinking I would need to split the string by numbers and sort each part, and I can sort the number parts using the solution above. Then where there are multiple strings that start the same way i.e section[i] = ('A_') I sort section[i 1] and work my way to the end. This feels very complicated though, so maybe there is a better way.

Edit: The data could be any mix of words and numbers. It could 'A_10x05', or it could be 'Item_A_10x05x200_Base_01'. So the solution has to be general.

CodePudding user response：

IIUC, you are trying to multiply the numbers in 10x05 - which you can do by passing a key function to sorted

def eval_result(s):
    prefix, op = s.split('_')
    num1, num2 = map(int, op.split('x'))
    return num1 * num2
sorted(s, key=eval_result)

Output

['A_10x05', 'A_10x50', 'A_10x100']

CodePudding user response：

I believe what you want is just to sort each part of the input strings separately - text parts alphabetically, numeric parts by numeric value, with no multiplications involved. If this is the case you will need a helper function:

from re import findall

s = ['A_10x5', 'Item_A_10x05x200_Base_01', 'A_10x100', 'B']

def fun(s):
    f = findall(r'\d |[A-Za-z_] ',s)
    return list(map(lambda x:int(x) if x.isdigit() else x, f))

sorted(s, key = fun)
['A_10x5', 'A_10x100', 'B', 'Item_A_10x05x200_Base_01']