How to convert a string with comma-delimited items to a list in Python?

Question

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 h

Answer 1

I usually use:

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

the strip remove spaces around words.

Answer 2

split() is your friend here. I will cover a few aspects of split() that are not covered by other answers.

• If no arguments are passed to split(), it would split the string based on whitespace characters (space, tab, and newline). Leading and trailing whitespace is ignored. Also, consecutive whitespaces are treated as a single delimiter.

Example:

>>> "   \t\t\none  two    three\t\t\tfour\nfive\n\n".split()
['one', 'two', 'three', 'four', 'five']

• When a single character delimiter is passed, split() behaves quite differently from its default behavior. In this case, leading/trailing delimiters are not ignored, repeating delimiters are not "coalesced" into one either.

Example:

>>> ",,one,two,three,,\n four\tfive".split(',')
['', '', 'one', 'two', 'three', '', '\n four\tfive']

So, if stripping of whitespaces is desired while splitting a string based on a non-whitespace delimiter, use this construct:

words = [item.strip() for item in string.split(',')]

• When a multi-character string is passed as the delimiter, it is taken as a single delimiter and not as a character class or a set of delimiters.

Example:

>>> "one,two,three,,four".split(',,')
['one,two,three', 'four']

To coalesce multiple delimiters into one, you would need to use re.split(regex, string) approach. See the related posts below.

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Related

• string.split() - Python documentation
• re.split() - Python documentation
• Split string based on regex
• Split string based on a regular expression

Answer 3

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"]

Answer 4

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'] 

Answer 5

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(',')]

Answer 6

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