Question :
Sorting a tuple that contains tuples
I have the following tuple, which contains tuples:
MY_TUPLE = (
('A','Apple'),
('C','Carrot'),
('B','Banana'),
)
I’d like to sort this tuple based upon the second value contained in inner-tuples (i.e., sort Apple, Carrot, Banana rather than A, B, C).
Any thoughts?
Answer #1:
from operator import itemgetter
MY_SORTED_TUPLE = tuple(sorted(MY_TUPLE, key=itemgetter(1)))
or without itemgetter:
MY_SORTED_TUPLE = tuple(sorted(MY_TUPLE, key=lambda item: item[1]))
Answer #2:
From Sorting Mini-HOW TO
Often there’s a built-in that will
match your needs, such as str.lower().
The operator module contains a number
of functions useful for this purpose.
For example, you can sort tuples based
on their second element using
operator.itemgetter():
>>> import operator
>>> L = [('c', 2), ('d', 1), ('a', 4), ('b', 3)]
>>> map(operator.itemgetter(0), L)
['c', 'd', 'a', 'b']
>>> map(operator.itemgetter(1), L)
[2, 1, 4, 3]
>>> sorted(L, key=operator.itemgetter(1))
[('d', 1), ('c', 2), ('b', 3), ('a', 4)]
Hope this helps.
Answer #3:
sorted(my_tuple, key=lambda tup: tup[1])
In other words, when comparing two elements of the tuple you’re sorting, sort based on the return value of the function passed as the key parameter.
Answer #4:
I achieved the same thing using this code, but your suggestion is great. Thanks!
templist = [ (line[1], line) for line in MY_TUPLE ]
templist.sort()
SORTED_MY_TUPLE = [ line[1] for line in templist ]
