Python Print On Standard Error
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Print Sys.stderr Comments In Python
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Python Eprint
takes a minute: Sign up print vs stderr up vote 23 down vote favorite 9 Are there any specific advantages or disadvantages to either print or stderr? python printing stderr share|improve this question edited Aug 5 at 15:15 Dawid Ferenczy
Python Redirect Stderr
4,12042638 asked Jun 2 '09 at 14:25 Tyler 94851522 add a comment| 4 Answers 4 active oldest votes up vote 30 down vote accepted They're just two different things. print generally goes to sys.stdout. It's worth knowing the difference between stdin, stdout, and stderr - they all have their uses. In particular, stdout should be used for normal program output, whereas stderr should be reserved only for error messages (abnormal program execution). There are utilities for splitting these streams, which allows standard error stream function in python users of your code to differentiate between normal output and errors. share|improve this answer edited Aug 5 at 15:17 Dawid Ferenczy 4,12042638 answered Jun 2 '09 at 14:29 Daniel Lew 54.8k23148158 12 Also note that stderr is unbuffered, which can be useful. –JimB Jun 2 '09 at 16:08 6 I’d tweak the wording of your answer to replace “program output” with “non-textual or non-status program output”. stderr also should not be reserved for error messages in all cases — for example, a program that downloads to stdout, which gets piped to another program, but prints download progress into stderr (which gets to ‘break out’ of the pipe). –Jeremy Visser Aug 9 '10 at 4:03 add a comment| up vote 74 down vote print can print on any file-like object, including sys.stderr. print >> sys.stderr, 'Text' The advantages of using sys.stderr for errors instead of sys.stdout are: If the user redirected stdout to a file, she still sees errors on the screen. It's not buffered, so if sys.stderr is redirected to a log file there are less chance that the program may crash before the error was logged. This answer written with Python 2 in mind. For Python 3, use print('Text', file=sys.stderr) instead. share|improve this answer edited May 25 '15 at 21:50 answered Jun 2 '09 at 14:31 Bastien Léonard 31.3k106181 1 +1. great! I wasn't aware of this property of 'print' –db42 May 21 '11 at 19:
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and lambda cannot have return statement policies of this site About Us Learn more about Stack Overflow the print(input()) company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags print( hello world end= o ) in python Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping each other. Join them; it only takes http://stackoverflow.com/questions/939866/print-vs-stderr a minute: Sign up stderr.write; printing strings up vote 3 down vote favorite 1 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 http://stackoverflow.com/questions/6663778/stderr-write-printing-strings 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? python stderr share|improve this question edited Jun 5 '12 at 23:21 user212218 asked Jul 12 '11 at 11:57 HasIq. 5014 add a comment| 4 Answers 4 active oldest votes up vote 7 down vote accepted 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)) share|improve this answer answered Jul 12 '11 at 11:59 mrbox 47329 Also, consider using the logging module to log. –Noufal Ibrahim Jul 12 '11 at 12:04 1 Of course logging is very usefull- but sometimes I it is better to log more details and print to stderr something different to mark that an error happened –mrbox Jul 12 '11 at 12:08 Thx! Works like a ch
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