PYTHON

sort tuple by first element python

a = [(5,8), (3,4), (9,7)]

#sort by first element in tuple
result = sorted(a, key=lambda tup: tup[0])

#OR to do inplace sort:

a.sorted(key = lambda tup: tup[0])

# output
[(3, 4), (5, 8), (9, 7)]

Sort python list by first element

li = [[1,4,7],[3,6,9],[2,59,8]]
li.sort(key=lambda x: int(x[0]))

Sort python list by first element

>>> lis = [[1,4,7],[3,6,9],[2,59,8]]
>>> lis.sort()
>>> lis
[[1, 4, 7], [2, 59, 8], [3, 6, 9]]