I have a fairly simple list (a number followed by a sentence), here in the right order:
-347 a negative number
-100 another negative number
-25 and again, a negative number
17 some text
25 foo bar
100 two same texts
100 two same texts (almost)
350 a positive number
I need to sort that list each time a new item is added.
I searched S.O. and found that answer :
Sorting in python - how to sort a list containing alphanumeric values?
The code I used is freakish’s, which goes :
import re
def convert(str):
return int("".join(re.findall("\d*", str)))
list1.sort(key=convert)
In order to better explain my problem, I shuffled the list and ran the code.
The result was :
17 some text
-25 and again, a negative number
25 foo bar
100 two same texts (almost)
100 two same texts
-100 another negative number
-347 a negative number
350 a positive number
What went wrong ? What is the precision in the code that would sort naturally the negative numbers?
Sort can accept a tuple, so first sort by the number, then by the text after
list_text = """-347 a negative number
-100 another negative number
-25 and again, a negative number
17 some text
25 foo bar
100 two same texts
100 two same texts (almost)
350 a positive number"""
list1 = list_text.split("\n")
list1.sort(key=lambda x: (int(x.split()[0]), x.split(" ",1)))
print("\n".join(list1))
The easiest approach, IMHO, would be to split the string to individual words, and then sort by the first word converted to an int
:
list1.sort(key = lambda x : int(x.split(" ")[0]))
EDIT:
As Keatinge, the above solution won't properly handle two strings that start with the same number. Using the entire string as a secondary search term should solve this issue:
list1.sort(key = lambda x : (int(x.split(" ")[0]), x)
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