How to sort the coordinate list?

Question

Suppose I have a coordinate list as the following:

list_ = [{'x':1,'y':2},{'x':1,'y':1},{'x':3,'y':3}]

I want to first sort x key, and then sort y key. So I expect:

list_ = [{'x':1,'y':1},{'x':1,'y':2},{'x':3:'y':3}]

How do I do?

Answer 1

Use the key parameter of sort/sorted. You pass a function that returns the key to sort upon. operator.itemgetter is an efficient way to generate the function:

>>> from operator import itemgetter
>>> list_ = [{'x':1,'y':2},{'x':1,'y':1},{'x':3,'y':3}]
>>> sorted(list_,key=itemgetter('x','y'))
[{'x': 1, 'y': 1}, {'x': 1, 'y': 2}, {'x': 3, 'y': 3}]