How do you convert a string into a list?

Say the string is like text = "a,b,c". After the conversion, text == ['a', 'b', 'c'] and hopefully text[0] == 'a', text[1] == 'b'?

Like this:

>>> text = 'a,b,c'
>>> text = text.split(',')
>>> text
[ 'a', 'b', 'c' ]

Alternatively, you can use eval() if you trust the string to be safe:

>>> text = 'a,b,c'
>>> text = eval('[' + text + ']')

Just to add on to the existing answers: hopefully, you’ll encounter something more like this in the future:

>>> word = 'abc'
>>> L = list(word)
>>> L
['a', 'b', 'c']
>>> ''.join(L)
'abc'

But what you’re dealing with right now, go with @Cameron‘s answer.

>>> word = 'a,b,c'
>>> L = word.split(',')
>>> L
['a', 'b', 'c']
>>> ','.join(L)
'a,b,c'

The following Python code will turn your string into a list of strings:

import ast
teststr = "['aaa','bbb','ccc']"
testarray = ast.literal_eval(teststr)

I don’t think you need to

In python you seldom need to convert a string to a list, because strings and lists are very similar

Changing the type

If you really have a string which should be a character array, do this:

In [1]: x = "foobar"
In [2]: list(x)
Out[2]: ['f', 'o', 'o', 'b', 'a', 'r']

Not changing the type

Note that Strings are very much like lists in python

Strings have accessors, like lists

In [3]: x[0]
Out[3]: 'f'

Strings are iterable, like lists

In [4]: for i in range(len(x)):
...:     print x[i]
...:     
f
o
o
b
a
r

TLDR

Strings are lists. Almost.

In case you want to split by spaces, you can just use .split():

a = 'mary had a little lamb'
z = a.split()
print z

Output:

['mary', 'had', 'a', 'little', 'lamb'] 

If you actually want arrays:

>>> from array import array
>>> text = "a,b,c"
>>> text = text.replace(',', '')
>>> myarray = array('c', text)
>>> myarray
array('c', 'abc')
>>> myarray[0]
'a'
>>> myarray[1]
'b'

If you do not need arrays, and only want to look by index at your characters, remember a string is an iterable, just like a list except the fact that it is immutable:

>>> text = "a,b,c"
>>> text = text.replace(',', '')
>>> text[0]
'a'

m = '[[1,2,3],[4,5,6],[7,8,9]]'

m= eval(m.split()[0])

[[1, 2, 3], [4, 5, 6], [7, 8, 9]]

All answers are good, there is another way of doing, which is list comprehension, see the solution below.

u = "UUUDDD"

lst = [x for x in u]

for comma separated list do the following

u = "U,U,U,D,D,D"

lst = [x for x in u.split(',')]

I usually use:

l = [ word.strip() for word in text.split(',') ]

the strip remove spaces around words.

To convert a string having the form a="[[1, 3], [2, -6]]" I wrote yet not optimized code:

matrixAr = []
mystring = "[[1, 3], [2, -4], [19, -15]]"
b=mystring.replace("[[","").replace("]]","") # to remove head [[ and tail ]]
for line in b.split('], ['):
    row =list(map(int,line.split(','))) #map = to convert the number from string (some has also space ) to integer
    matrixAr.append(row)
print matrixAr

# to strip `,` and `.` from a string ->

>>> 'a,b,c.'.translate(None, ',.')
'abc'

You should use the built-in translate method for strings.

Type help('abc'.translate) at Python shell for more info.

Using functional Python:

text=filter(lambda x:x!=',',map(str,text))

Example 1

>>> email= "myemailid@gmail.com"
>>> email.split()
#OUTPUT
["myemailid@gmail.com"]

Example 2

>>> email= "myemailid@gmail.com, someonsemailid@gmail.com"
>>> email.split(',')
#OUTPUT
["myemailid@gmail.com", "someonsemailid@gmail.com"]