How to delete blank lines in a file??

[joe82]

Hello everyone,

My file has lines like:

>9|102396631|genome.....

CCACTTTCTCTCCGCGCTGGGTTGAACATGGTACATCAGACTCCCTGAATCTGTCAGATC

TCTTGGTTGCTGTTGACAACTAAGACTTCGGAGCCTGGAG_GATTTGTTGAGGGGGAGCA

GTTCTGGGTGTCCTCTGCTGTGACTGGGCTCCCGGCCTCTTGATAATGCGCAACAGCTGC

GGTAGAACATCTCATTCCCAG

>9|102362951|ENSRNOS....

I want to delete blank lines from this file please help me...

Thanks

[shadwickman]

Just read the file as-is and then write the output with the lines that aren't blank. Here's an example:

# Read lines as a list
fh = open("myfile", "r")
lines = fh.readlines()
fh.close()

# Weed out blank lines with filter
lines = filter(lambda x: not x.isspace(), lines)

# Write
fh = open("output", "w")
fh.write("".join(lines))
# should also work instead of joining the list:
# fh.writelines(lines)
fh.close()

Also, if you don't understand my lambda expression there, here's a longer route instead of using filter :

fh = open("myfile", "r")
lines = fh.readlines()
fh.close()

keep = []
for line in lines:
    if not line.isspace():
        keep.append(line)

fh = open("output", "w")
fh.write("".join(keep))
# should also work instead of joining the list:
# fh.writelines(keep)
fh.close()

All this is untested as I'm at work! But this should give you an idea of how to do it.
Hope that helps!

[vegaseat]

Actually, the empty lines in your data do not contain any spaces. Change the code a little to reflect this ...

# your data file read() ...
data_str = """\
>9|102396631|genome.....

CCACTTTCTCTCCGCGCTGGGTTGAACATGGTACATCAGACTCCCTGAATCTGTCAGATC

TCTTGGTTGCTGTTGACAACTAAGACTTCGGAGCCTGGAG_GATTTGTTGAGGGGGAGCA

GTTCTGGGTGTCCTCTGCTGTGACTGGGCTCCCGGCCTCTTGATAATGCGCAACAGCTGC

GGTAGAACATCTCATTCCCAG

>9|102362951|ENSRNOS....
"""

# create a list of lines
# or get the list directly with data file readlines()
mylist = data_str.split('\n')

new_str = ""
for item in mylist:
    if item:
        new_str += item + '\n'

print(new_str)

"""
my output -->
>9|102396631|genome.....
CCACTTTCTCTCCGCGCTGGGTTGAACATGGTACATCAGACTCCCTGAATCTGTCAGATC
TCTTGGTTGCTGTTGACAACTAAGACTTCGGAGCCTGGAG_GATTTGTTGAGGGGGAGCA
GTTCTGGGTGTCCTCTGCTGTGACTGGGCTCCCGGCCTCTTGATAATGCGCAACAGCTGC
GGTAGAACATCTCATTCCCAG
>9|102362951|ENSRNOS....
"""

[joe82]

Thanks a lot ...:)