Sort order of lists in multidimensional array in Python

Question

I would like to turn this data in Python (sorted alphabetically):

test = [['ma', 'e', 'wa', 'ka'], ['ma', 'haa', 'laa'], ['ma', 'ka', 'm', 'haa', 'laa', 'ca', 'j', 'ra'], ['ma', 'ra'], 'ma']

Into a multidimensional array with its items sorted by the amount of items in each list like this:

test = ['ma', ['ma', 'ra'], ['ma', 'haa', 'laa'], ['ma', 'e', 'wa', 'ka'], ['ma', 'ka', 'm', 'haa', 'laa', 'ca', 'j', 'ra']]

If you just looked at the length, I'd like it to go from [4, 3, 8, 2, 1] to [1, 2, 3, 4, 8] but I don't necessarily want the solution to be specific to this example.

Raul Guiu · Accepted Answer · 2014-03-23 15:43:19Z

5

test = sorted(test, key=lambda x: len(x) if type(x)==list else 1)

I tried that:

>>> test = [['ma', 'e', 'wa', 'ka'], ['ma', 'haa', 'laa'], ['ma', 'ka', 'm', 'haa', 'laa', 'ca', 'j', 'ra'], ['ma', 'ra'], 'ma']
>>> test = sorted(test, key=lambda x: len(x) if type(x)==list else 1)
>>> test
['ma', ['ma', 'ra'], ['ma', 'haa', 'laa'], ['ma', 'e', 'wa', 'ka'], ['ma', 'ka', 'm', 'haa', 'laa', 'ca', 'j', 'ra']]

the only odd thing is that not all elements in your original list are list, you included strings and list, that is why I had to add the condition if type(x)==list else 1

answered Mar 23, 2014 at 15:43

Raul Guiu

2,41423 silver badges39 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Harrichael Over a year ago

I recommend turning items that you mean as single lists and make them actual lists. You will avoid special handling scattered throughout your code as seen here. Additionally, it is what you mean.

aha · Accepted Answer · 2014-03-23 15:45:23Z

1

One solution:

sorted(test, key=lambda x: isinstance(x,list) and len(x) or 1)

answered Mar 23, 2014 at 15:45

aha

4,6744 gold badges26 silver badges27 bronze badges

Collectives™ on Stack Overflow

Sort order of lists in multidimensional array in Python

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related