CODEWITHSUNDEEP
pythonstderr
HasIq.
HasIq.

Reputation: 117

stderr.write; printing strings

I am new to Python and having some trouble with the stderr.write function. I will try to illustrate it with code. Before I was doing this:

print "Unexpected error! File {0} could not be converted." .format(src)

But then I wanted to separate the error messages from other status messages so I tried doing this:

sys.stderr.write "Unexpected error! File %s could not be converted." src

But this results in error. I googled it as well but i couldn't find anything. Could anyone please help me out here. How can I print the string src using stderr.write?

Upvotes: 3

Views: 9255

Answers (4)

Ignacio Vazquez-Abrams
Ignacio Vazquez-Abrams

Reputation: 798436

Functions in Python need to be followed by parens ((...)), optionally containing arguments, in order to be invoked.

sys.stderr.write("Unexpected error! File %s could not be converted.\n" % (src,))

Upvotes: 1

Artsiom Rudzenka
Artsiom Rudzenka

Reputation: 29093

You have missed (,) and %:

import sys
sys.stderr.write("Unexpected error! File %s could not be converted." % src)

Upvotes: 0

unutbu
unutbu

Reputation: 879073

sys.stderr.write is a function, so to call the function, you need to use parentheses around the argument:

In [1]: src='foo'

In [2]: sys.stderr.write("Unexpected error! File %s could not be converted."%src)
Unexpected error! File foo could not be converted.

Note that as of Python3, print is also a function and will also require parentheses.

Upvotes: 0

mrbox
mrbox

Reputation: 824

In Python 2.x:

sys.stderr.write("Unexpected error! File %s could not be converted." % src)

Or, in Python 2.x and 3.x:

sys.stderr.write("Unexpected error! File {0} could not be converted.".format(src))

Upvotes: 8

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