Split by certain pattern in python

Question

Hi everyone i have a pattern (using django)

[[u'13'], [u'12', u'23'], [u'30', u'31']]

and i want to spilt this and want to append into a list like [13,12,23,30,31] I know this can be done using regular expression but unable to make regualr expression for that. Please help into this Thanks in advance.

What do you mean *"a pattern"*? That looks like a list of lists of strings, why do you think you need a regex? — jonrsharpe, Jun 18 '17 at 07:54
Yes jon it is a list of lists. but i want a single list of containing all values. — Cp Verma, Jun 18 '17 at 07:57
So you want to *flatten* the list, try searching for that. But it doesn't need a regular expression. — jonrsharpe, Jun 18 '17 at 07:58

omri_saadon · Accepted Answer · 2017-06-18T08:02:39.683

1

You can use the ast library in order to make the string a python list.

After, iterate through the list and chain all items into one list.

import ast

st = "[[u'13'], [u'12', u'23'], [u'30', u'31']]"

li = ast.literal_eval(st) # you can use this library in order to make the string a python list.
new_li = [item for inner_list in li for item in inner_list]

print (new_li)

ast.literal_eval(node_or_string)

Safely evaluate an expression node or a Unicode or Latin-1 encoded string containing a Python literal or container display.

edited Jun 18 '17 at 08:02

answered Jun 18 '17 at 07:59

omri_saadon

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Why would you special case lists of a certain length when flattening? – jonrsharpe Jun 18 '17 at 08:01
@jonrsharpe , No need, I've updated my answer. Thanks. – omri_saadon Jun 18 '17 at 08:03
Hi Omri it is showing error `malformed string` – Cp Verma Jun 18 '17 at 08:12
Thanks...it is working – Cp Verma Jun 18 '17 at 08:17

score 0 · Answer 2 · answered Jun 18 '17 at 08:13

0

You could do in python3,

In [8]: [int(s) for i in a for s in i]
Out[8]: [13, 12, 23, 30, 31]

answered Jun 18 '17 at 08:13

zaidfazil

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i am using python 2.7 – Cp Verma Jun 18 '17 at 08:15

Split by certain pattern in python

2 Answers2