fileinput.input - newbie question

[martijn]

I'm testing some writing/reading with a file and i'm not sure if it is
possible to print/use the line with fileinput.input inplace=1 (see
below)


import fileinput
thefile = fileinput.input('bla.txt',inplace=1,backup='.bak')
for line in thefile:
if line != "1\n":
print line,

#is it possible to 'use' / print the 'line' on the screen here?

thefile.close()

When its not possible then I use 2 file's filein.txt,fileout.txt

Thanks,
GC-Martijn

 

[Peter Otten]

I'm testing some writing/reading with a file and i'm not sure if it is
possible to print/use the line with fileinput.input inplace=1 (see
below)

fileinput.input(inplace=True) redirects stdout to the file given as its
first parameter. Instead of appearing on the screen the output of print
statements is therefore written to the file currently being read (there are
actually two files, just like in your alternative approach).

You can work around redirection by saving a copy of the original stdout:

import fileinput

import sys
original_stdout = sys.stdout

thefile = fileinput.input('bla.txt',inplace=1,backup='.bak')
for line in thefile:
if line != "1\n":

# this is written to 'bla.txt'

print line,

# this is written to the screen (if you don't
# redirect stdout externally)
print >> original_stdout, line,

#is it possible to 'use' / print the 'line' on the screen here?

thefile.close()

When its not possible then I use 2 file's filein.txt,fileout.txt

I would prefer that for its conceptual simplicity.

Peter

 

[martijn]

That works fine

Thanks for the fast help.

GC-Martijn