What does this code mean: "print >> sys.stderr"
print >> sys.stderr开发者_StackOverflow中文版, "Error in atexit._run_exitfuncs:"
Why print '>>' in front of sys.stderr
?
Thanks.
This syntax means writes to a file object (sys.stderr
in this case) instead of standard output. [Link]
In Python 3.0, print
becomes a function instead of a statement: [Link]
print("Error in atexit._run_exitfuncs:", file=sys.stderr)
From the Python documentation:
print also has an extended form, defined by the second portion of the syntax described above. This form is sometimes referred to as “print chevron.” In this form, the first expression after the >> must evaluate to a “file-like” object, specifically an object that has a write() method as described above. With this extended form, the subsequent expressions are printed to this file object. If the first expression evaluates to None, then sys.stdout is used as the file for output.
精彩评论