CODEWITHSUNDEEP
python
Dan
Dan

Reputation: 1029

Splitting a list

I've scoured various resources and can't figure out how to do a rather simple operation.

Right now, I have a list as follows:

li = [['a=b'],['c=d']]

I want to transform this into:

li = [['a','b'],['c','d']]

As I understand it, split("=") only applies to string types. Is there an equivalent method for lists?

Pardon the simplicity of my question...

-Dan

Upvotes: 1

Views: 301

Answers (6)

chryss
chryss

Reputation: 7519

Presuming each sublist consists of individual strings of the form a=b:

>>> [el[i].split('=') for el in li for i in range(len(el))]
[['a', 'b'], ['c', 'd']]

(Indeed, what you're splitting is the inner string a=b. So the split() string method works fine.)

EDIT: A much more elegant way of doing this double list comprehension is:

>>> [a.split('=') for el in li for a in el]
[['a', 'b'], ['c', 'd']]

There have been a number of good suggestions made, so the OP should be able to learn a good amount of Python for it. Important to remember is that what is being split is li[i][j], ie an item of the list that is an item of the list li.

Upvotes: 0

g.d.d.c
g.d.d.c

Reputation: 47968

You want this:

[x[0].split('=') for x in li]
# prints [['a', 'b'], ['c', 'd']]

To grab a question from a comment further down the post, the reason split works for x[0] is that x represents the inner list. That's accomplished by the for x in li. Also, I fixed mine to read for x in li and not for x in test as I had assigned your examples to a variable called 'test' on my system.

Upvotes: 9

txwikinger
txwikinger

Reputation: 3034

You can do it with this:

[k[0].split("=") for k in li]

Upvotes: 0

Gangadhar
Gangadhar

Reputation: 1903

Is this what you are looking for ? map(lambda y:y.split('='),map(lambda x:x[0], li))

Upvotes: 0

Felix Kling
Felix Kling

Reputation: 816232

You can use map():

>>> li = [['a=b'],['c=d']]
>>> map(lambda x: x[0].split('='), li)
[['a', 'b'], ['c', 'd']]

This traverses the list li and applies the lambda function to every element. As every element of the list is again a list with one element, x[0] takes this element, which is a string, splits it and returns a new list with both values.

Upvotes: 3

Freiheit
Freiheit

Reputation: 8757

Warning - its been a while since I did any python, but your issue is more general.

You are correct in that split applies to strings.

What you need to do is split the VALUE contained in your list not the list itself.

So you would do something like

newValue = split('=', li[0][0]) 
li[0] = newValue

Upvotes: 0

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