Python Print To System Error
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Print Sys.stderr Comments In Python
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Python Redirect Stderr
to stderr in Python? up vote 676 down vote favorite 103 I've come across at least three ways to print to stderr: import sys print >> sys.stderr, 'spam' sys.stderr.write('spam\n') from __future__ import print_function print('spam', file=sys.stderr) It seems to contradict zen of Python #13 †, so what's the preferred way to do it? Are there any advantages or disadvantages to one way or the other? standard error stream function in python † There should be one — and preferably only one — obvious way to do it. python printing stderr zen share|improve this question edited Jun 21 '15 at 22:27 Peter Mortensen 10.3k1369107 asked Apr 7 '11 at 0:59 wim 77k24152241 27 The first way listed is one of the many things removed in Python 3. The consensus seems to be that the >> syntax was ugly anyway, and since print is now a function, the syntax would never work. –Steve Howard Aug 5 '11 at 21:50 14 Here's another one to add to your list: os.write(2, "spam\n") –Will Hardy Jul 10 '13 at 10:54 4 I use: sys.exit('Error:
you have probably seen some. There are (at least) two distinguishable kinds of errors: syntax errors and exceptions. 8.1. Syntax Errors¶ Syntax errors, also known as parsing errors, are perhaps the most
File=sys.stderr Invalid Syntax
common kind of complaint you get while you are still learning Python: >>> while lambda cannot have return statement True print('Hello world') File "
you have probably seen some. There are (at least) two distinguishable kinds of errors: syntax errors and exceptions. 8.1. https://docs.python.org/2.7/tutorial/errors.html Syntax Errors¶ Syntax errors, also known as parsing errors, are perhaps https://docs.python.org/3/whatsnew/3.0.html the most common kind of complaint you get while you are still learning Python: >>> while True print 'Hello world' File "
2.6. Python 3.0, also known as "Python 3000" or "Py3K", is the first ever intentionally backwards incompatible Python release. There are more changes than in a typical release, and more that are important for all Python users. Nevertheless, after digesting the changes, you'll find that Python really hasn't changed all that much - by and large, we're mostly fixing well-known annoyances and warts, and removing a lot of old cruft. This article doesn't attempt to provide a complete specification of all new features, but instead tries to give a convenient overview. For full details, you should refer to the documentation for Python 3.0, and/or the many PEPs referenced in the text. If you want to understand the complete implementation and design rationale for a particular feature, PEPs usually have more details than the regular documentation; but note that PEPs usually are not kept up-to-date once a feature has been fully implemented. Due to time constraints this document is not as complete as it should have been. As always for a new release, the Misc/NEWS file in the source distribution contains a wealth of detailed information about every small thing that was changed. Common Stumbling Blocks¶ This section lists those few changes that are most likely to trip you up if you're used to Python 2.5. Print Is A Function¶ The print statement has been replaced with a print() function, with keyword arguments to replace most of the special syntax of the old print statement (PEP 3105). Examples: Old: print "The answer is", 2*2 New: print("The answer is", 2*2) Old: print x, # Trailing comma suppresses newline New: print(x, end=" ") # Appends a space instead of a newline Old: print # Prints a newline New: print() # Y