CODEWITHSUNDEEP
pythonpython-3.xlistsorting
user9270170
user9270170

Reputation:

How to sort list by the numbers in a string?

I have a list of string containing numbers like this:

['line_1.jpg Word930\n', 'line_10.jpg Word203\n', 'line_2.jpg Word31\n', 'line_100.jpg Word7\n',  'line_3.jpg Word60\n', 'line_4.jpg Word52\n']

I want to sort the numbers in the string before the space in each string from small to large,I want this result:

['line_1.jpg Word930\n', 'line_2.jpg Word31\n', 'line_3.jpg Word60\n',
'line_4.jpg Word52\n', 'line_10.jpg Word203\n', 'line_100.jpg Word7\n']

I use this code to sort list:

myList=['line_1.jpg Word930\n', 'line_10.jpg Word203\n', 'line_2.jpg Word31\n', 'line_100.jpg Word7\n',  'line_3.jpg Word60\n', 'line_4.jpg Word52\n']
myList.sort()
print(myList)

But the result is:

['line_1.jpg Word930\n', 'line_10.jpg Word203\n', 'line_100.jpg Word7\n', 'line_2.jpg Word31\n', 'line_3.jpg Word60\n', 'line_4.jpg Word52\n']

This is not right,how to fix the code?

Upvotes: 0

Views: 87

Answers (3)

RoadRunner
RoadRunner

Reputation: 26315

We could split the string on "." to get the filename, split again on "_", then get the number from the last item and convert to an integer. Then we can pass this to the key function of sorted(). 

lst = ['line_1.jpg Word930\n', 'line_2.jpg Word31\n', 'line_3.jpg Word60\n', 'line_4.jpg Word52\n', 'line_10.jpg Word203\n', 'line_100.jpg Word7\n']

print(sorted(lst, key=lambda x: int(x.split(".")[0].split("_")[-1])))
# ['line_1.jpg Word930\n', 'line_2.jpg Word31\n', 'line_3.jpg Word60\n', 'line_4.jpg Word52\n', 'line_10.jpg Word203\n', 'line_100.jpg Word7\n']

Upvotes: 1

Leo Arad
Leo Arad

Reputation: 4472

You can sorted the list like

myList.sort(key=lambda x: int(x[x.find("_")+ 1:x.find(".")]))

That will sort the list base on the number of the file.

Upvotes: 1

han solo
han solo

Reputation: 6590

You can use re to get the value and use that in the list.sort's keyfunction like,

>>> import re
>>> x
['line_1.jpg Word930\n', 'line_10.jpg Word203\n', 'line_2.jpg Word31\n', 'line_100.jpg Word7\n', 'line_3.jpg Word60\n', 'line_4.jpg Word52\n']
>>> x.sort(key=lambda x: int(re.search(r'line_(\d+).*', x).group(1)))
>>> x
['line_1.jpg Word930\n', 'line_2.jpg Word31\n', 'line_3.jpg Word60\n', 'line_4.jpg Word52\n', 'line_10.jpg Word203\n', 'line_100.jpg Word7\n']
>>>

Upvotes: 2

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