How to open a file for both reading and writing

Question

Is there a way to open a file for both reading and writing   As a workaround  I open the file for writing  close it  then open it again for reading  But is there a way to open a file for both reading and writing

User · Answer

Here s how you read a file  and then write to it  overwriting any existing data   without closing and reopening   with open filename   r    as f      data   f read       f seek 0      f write output      f truncate

User · Answer

I have tried something like this and it works as expected   f   open  c   log log    r b   f write   x5F x9D x3E   f read 100  f close     Where      f read size  - To read a file   s contents  call f read size   which   reads some quantity of data and returns it as a string    And      f write string  writes the contents of string to the file  returning   None    Also if you open Python tutorial about reading and writing files you will find that       r   opens the file for both reading and writing        On Windows   b  appended to the mode opens the file in binary mode  so   there are also modes like  rb    wb   and  r b

User · Answer

Summarize the I O behaviors             Mode             r      r      w      w      a      a        --------------------     --     --     --     --     --     --               Read                                                                Write                                                                Create                                                               Cover                                                        Point in the beginning                                                  Point in the end                                                  and the decision branch

User · Answer

r  is the canonical mode for reading and writing at the same time  This is not different from using the fopen   system call since file     open   is just a tiny wrapper around this operating system call

[python] How to open a file for both reading and writing?

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