问题
I need to sort a list of tuples in Python by a specific tuple element, let's say it's the second element in this case. I tried
sorted(tupList, key = lambda tup: tup[1])
I have also tried
sorted(tupList, key = itemgetter(1))
'''i imported itemgetter, attrgetter, methodcaller from operator'''
but the list was returned the same both times. I checked
sorting tuples in python with a custom key
sort tuples in lists in python
https://wiki.python.org/moin/HowTo/Sorting
回答1:
I'm guessing you're calling sorted but not assigning the result anywhere. Something like:
tupList = [(2,16), (4, 42), (3, 23)]
sorted(tupList, key = lambda tup: tup[1])
print(tupList)
sorted creates a new sorted list, rather than modifying the original one. Try:
tupList = [(2,16), (4, 42), (3, 23)]
tupList = sorted(tupList, key = lambda tup: tup[1])
print(tupList)
Or:
tupList = [(2,16), (4, 42), (3, 23)]
tupList.sort(key = lambda tup: tup[1])
print(tupList)
来源：https://stackoverflow.com/questions/29656499/sorting-tuples-by-element-value-in-python