How to remove empty lines with or without whitespace

Try list comprehension and string.strip():

>>> mystr = "L1nL2nnL3nL4n  nnL5"
>>> mystr.split('n')
['L1', 'L2', '', 'L3', 'L4', '  ', '', 'L5']
>>> [line for line in mystr.split('n') if line.strip()]
['L1', 'L2', 'L3', 'L4', 'L5']

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

I also tried regexp and list solutions, and list one is faster.

Here is my solution (by previous answers):

text = "n".join([ll.rstrip() for ll in original_text.splitlines() if ll.strip()])

If you are not willing to try regex (which you should), you can use this:

s.replace('nn','n')

Repeat this several times to make sure there is no blank line left. Or chaining the commands:

s.replace('nn','n').replace('nn','n')

_{Just to encourage you to use regex, here are two introductory videos that I find intuitive:
• Regular Expressions (Regex) Tutorial
• Python Tutorial: re Module}

My version:

while '' in all_lines:
    all_lines.pop(all_lines.index(''))

Same as what @NullUserException said, this is how I write it:

removedWhitespce = re.sub(r'^s*$', '', line)

Surprised a multiline re.sub has not been suggested (Oh, because you’ve already split your string… But why?):

>>> import re
>>> a = "Foon nBarnBaznn   Garplyn  n"
>>> print a
Foo

Bar
Baz

        Garply


>>> print(re.sub(r'ns*n','n',a,re.MULTILINE))
Foo
Bar
Baz
        Garply

>>> 

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

you can simply use rstrip:

    for stuff in largestring:
        print(stuff.rstrip("n")

Use positive lookbehind regex:

re.sub(r'(?<=n)s+', '', s, re.MULTILINE)

When you input:

foo
<tab> <tab>

bar

The output will be:

foo
bar

str_whith_space = """
    example line 1

    example line 2
    example line 3

    example line 4"""

new_str = 'n'.join(el.strip() for el in str_whith_space.split('n') if el.strip())
print(new_str)

Output:

""" <br>
example line 1 <br>
example line 2 <br>
example line 3 <br>
example line 4 <br>
"""

You can combine map and strip to remove spaces and use filter(None, iterable) to remove empty elements:

string = "an nnb"
list_of_str = string.split("n")
list_of_str = filter(None, map(str.strip, list_of_str))
list(list_of_str)

Returns: ['a', 'b']

 html_content = [l for l in html_content.splitlines() if l.rstrip()]
 html_content = "n".join(html_content)