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+--- Thread: "Anything else expression" in Python (/thread-11067.html)
"Anything else expression" in Python - spedy93 - Jun-21-2018
Hello, I´m new in programming, I am trying to erase something from the lines of a file,
example:
file is made of to colums:
xxxx zzzz
aaaa tttt
dddd nnn
I want to erase the second colum, what I am trying to do is to use the replace funtion, like this: (there a common pattern it is " XXXX" two spaces and the letters beyond). my code is something like this:
var1=(" *")
var2=("---")
f = open("archive.txt",'r')
change = f.read()
change = change.replace(var1,var2)
f.close()
new = open("newarchive.txt",'w')
new.write(change)
new.close()
the problem is the regular expression I am using " var1=(" *") "
" *" it is not working it does no match my lines, I have tried literally everything I found in internet but no luck
if I try:
var1=(" ")
var2=("---")
f = open("archive.txt",'r')
change = f.read()
change = change.replace(var1,var2)
f.close()
new = open("newarchive.txt",'w')
new.write(change)
new.close()
it replace only the two spaces with --- "xxxx---zzzz" and I need only the "xxxx---" with out the text beyond (zzzz)
what regular expression match " something" (spaces plus some alphanumeric text?) ? thanks for your time.
RE: "Anything else expression" in Python - wavic - Jun-21-2018
For example:
>>> data="""xxxx zzzz
... aaaa tttt
... dddd nnn"""
>>> new_data = []
>>> for line in data.split('\n'):
... new_data.append(f"{line[:line.index(' ')]}\n")
...
>>> new_data
['xxxx\n', 'aaaa\n', 'dddd\n']
# move the cursor at the beginning of the file
>>> file_object.seek(0)
# the file should be open in 'r+' mode ( reading and writing )
>>> file_object.writelines(new_data)