How to remove empty lines with or without whitespace in Python

Question

I have large string which I split by newlines. How can I remove all lines that are empty, (whitespace only)?

pseudo code:

for stuff in largestring:
          


        

Answer 1

Try list comprehension and string.strip():

>>> mystr = "L1\nL2\n\nL3\nL4\n  \n\nL5"
>>> mystr.split('\n')
['L1', 'L2', '', 'L3', 'L4', '  ', '', 'L5']
>>> [line for line in mystr.split('\n') if line.strip() != '']
['L1', 'L2', 'L3', 'L4', 'L5']

Answer 2

Using regex:

if re.match(r'^\s*$', line):
    # line is empty (has only the following: \t\n\r and whitespace)

Using regex + filter():

filtered = filter(lambda x: not re.match(r'^\s*$', x), original)

As seen on codepad.

Answer 3

lines = bigstring.split('\n')
lines = [line for line in lines if line.strip()]

Answer 4

I use this solution to delete empty lines and join everything together as one line:

match_p = re.sub(r'\s{2}', '', my_txt) # my_txt is text above