Remove newline/empty characters in Python string

Question

Well, this may sound repeat, but I've tried all possibilities like str.strip(), str.rstrip(), str.splitline(), also if-else check like:

if str is not '' or str is not '\n':
    print str

But I keep getting newlines in my output.

I'm storing the result of os.popen:

list.append(os.popen(command_arg).read())

When I do print list I get

['output1', '', 'output2', 'output3', '', '', '','']

My aim is to get

output1
output2
output3

instead of

    output1
  <blank line>
    output2
    output3
 <blank line>    
 <blank line>

Solution 1

I'd recommend for your case:

if str.strip():
    print str

instead of

if str is not '' or str is not '\n':
    print str

Important: Testing for string equality must be done using s == "..." rather than with s is "...".

Solution 2

This is an interesting case for applying the De-Morgan's Theorm.

You want to print strings that are not '' or \n.

That is,if str=='' or str =='\n', then don't print.

Hence while negating the above statement,You will have to apply the de morgan's theorm.

So,You will have to use if str !='' and str != '\n' then print

Solution 3

filter(str.strip, ['output1', '', 'output2', 'output3', '', '', '',''])

Comments

[Johannes Charra]

Good point. :) Still, comparing strings with is is error-prone. Consider: a = "abc\n"; b = a[-1:]; print b is "\n"

[aldeb]

l.remove('') will only remove the first '' in the list. I think the OP wants to remove all of them

[Vaibhav Jain]

Then try this :` >>> ll=['1','',''] >>> filter(None, ll) ['1']`

[volcano]

You've beat me to that :)

[volcano]

simply s not in (' ', '\n) will work (and str is class name in Python)