Convert strings to list Python

Question

list_val = '["apple", "blue", "green", "orange", "cherry", "white", "red", "violet"]'
print type(list_var)
str
print type(list_var[0])
'['

I read list_val values from a file and how to convert list_var to list ? so that list_var [0] should be 'apple'.

• Avihoo Mamka: Why not configure list_val as list and for each value, just append the item to the list?
• Karl Knechtel: How did the file end up like that in the first place? Are you trying to remember some list contents between runs of the program?

Answer 1

>>> list_val = '["apple", "blue", "green", "orange", "cherry", "white", "red", "violet"]'
>>> 
>>> from ast import literal_eval
>>> list_val = literal_eval(list_val)
>>> list_val[0]
'apple'

Answer 2

I recommend you use json.

import json
list_val = '["apple", "blue", "green", "orange", "cherry", "white", "red", "violet"]'
a = json.loads(list_val)
print a
# [u'apple', u'blue', u'green', u'orange', u'cherry', u'white', u'red', u'violet']
print type(a)
# <type 'list'>
print a[0]
# 'apple'

• John La Rooy: This certainly works for the example input. The best choice depends on matching the source encoding to the decoder. The origin may very well be JSON in this case.

Answer 3

you can use eval function. Be careful what you pass to eval though, malicious things can happen!

list_var = eval(list_val)

• The6thSense: eval is evil please use literal_eval instead

Answer 4

Another way is using regex:

>>> import re
>>> list_val = '["apple", "blue", "green", "orange", "cherry", "white", "red", "violet"]'
>>> result = re.findall(r'\"([^\"]+)\"', list_val)
>>> result[0]
'apple'