How to output to the console and file

Question

I m trying to find out a way in python to redirect the script execution log to a file as well as stdout in a pythonic way  Is there any easy way of achieving this

User · Answer

I just want to build upon Serpens answer and add the line:

logger.setLevel('DEBUG')

This will allow you to chose what level of message gets logged.

For example in Serpens example,

logger.info('Info message')

Will not get recorded as it defaults to only recording Warnings and above.

More about levels used can be read about here

User · Answer

Use logging module  http   docs python org library logging html    import logging  logger   logging getLogger  scope name    file log handler   logging FileHandler  logfile log   logger addHandler file log handler   stderr log handler   logging StreamHandler   logger addHandler stderr log handler     nice output format formatter   logging Formatter    asctime s -   name s -   levelname s -   message s   file log handler setFormatter formatter  stderr log handler setFormatter formatter   logger info  Info message   logger error  Error message

User · Answer

Probably the shortest solution   def printLog  args    kwargs       print  args    kwargs      with open  output out   a   as file          print  args    kwargs  file file   printLog  hello world     Writes  hello world  to sys stdout and to output out and works exactly the same way as print     Note  Please do not specify the file argument for the printLog function  Calls like printLog  test  file  output2 out   are not supported

User · Answer

Here s a small improvement that to  UltraInstinct s Tee class  modified to be a context manager and also captures any exceptions   import traceback import sys    Context manager that copies stdout and any exceptions to a log file class Tee object       def   init   self  filename           self file   open filename   w           self stdout   sys stdout      def   enter   self           sys stdout   self      def   exit   self  exc type  exc value  tb           sys stdout   self stdout         if exc type is not None              self file write traceback format exc            self file close        def write self  data           self file write data          self stdout write data       def flush self           self file flush           self stdout flush     To use the context manager   print  Print   with Tee  test txt        print  Print Write       raise Exception  Test   print  Print

User · Answer

Create an output file and custom function   outputFile   open  outputfile log    w    def printing text       print text      if outputFile          outputFile write str text     Then instead of print text  in your code  call printing function   printing  START   printing datetime datetime now    printing  COMPLETE   printing datetime datetime now

User · Answer

I came up with this  untested   import sys  class Tee object       def   init   self   files           self files   files     def write self  obj           for f in self files              f write obj              f flush     If you want the output to be visible immediately     def flush self            for f in self files              f flush    f   open  out txt    w   original   sys stdout sys stdout   Tee sys stdout  f  print  test     This will go to stdout and the file out txt   use the original sys stdout   original print  This won t appear on file     Only on stdout f close     print gt  gt xyz in python will expect a write   function in xyz  You could use your own custom object which has this  Or else  you could also have sys stdout refer to your object  in which case it will be tee-ed even without  gt  gt xyz

User · Answer

The easiest solution is to redirect the standard output  In your python program file use the following   if   name         main        sys stdout   open  file log    w       sys stdout   open   dev null    w      main     Any std output  e g  the output of print  hi there   will be redirected to file log or if you uncomment the second line  any output will just be suppressed

User · Answer

You should use the logging library  which has this capability built in  You simply add handlers to a logger to determine where to send the output

[python] How to output to the console and file?

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