What s the difference between r and a when open file in python

Question

I have try r  and a  to open file and read and write  but  r   and  a   are all append the str to the end of the file   So  what s the difference between r  and a       Add   I have found the reason    I have read the file object and forgot to seek 0  to set the location to the begin

User · Answer

If you have used them in C  then they are almost same as were in C   From the manpage of fopen   function   -        r    -   Open for reading and writing   The stream is positioned at   the        beginning of the file    a    -   Open for reading and writing   The file is created if it does   not        exist   The stream is positioned at the end of the file   Subse-        quent writes to the file will always end up at the then current        end of file  irrespective of any intervening fseek 3  or similar

User · Answer

One difference is for r  if the files does not exist  it ll not be created and open fails  But in case of a  the file will be created if it does not exist

User · Answer

Python opens files almost in the same way as in C    r   Open for reading and writing  The stream is positioned at the beginning of the file  a   Open for reading and appending  writing at end of file   The file is created if it does not exist  The initial file position for reading is at the beginning of the file  but output is appended to the end of the file  but in some Unix systems regardless of the current seek position

[python] What's the difference between 'r+' and 'a+' when open file in python?

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