Write variable to file including name

Question

Let s say I have the following dictionary in a small application    dict     one   1   two   2    What if I would like to write the exact code line  with the dict name and all  to a file  Is there a function in python that let me do it  Or do I have to convert it to a string first  Not a problem to convert it  but maybe there is an easier way   I do not need a way to convert it to a string  that I can do  But if there is a built in function that does this for me  I would like to know   To make it clear  what I would like to write to the file is   write to file  dict     one   1   two   2

User · Answer

The default string representation for a dictionary seems to be just right:

>>> a={3: 'foo', 17: 'bar' }
>>> a
{17: 'bar', 3: 'foo'}
>>> print a
{17: 'bar', 3: 'foo'}
>>> print "a=", a
a= {17: 'bar', 3: 'foo'}

Not sure if you can get at the "variable name", since variables in Python are just labels for values. See this question.

User · Answer

You could do   import inspect  mydict     one   1   two   2   source   inspect getsourcelines inspect getmodule inspect stack   0  0    0  print  x for x in source if x startswith  mydict         Also  make sure not to shadow the dict builtin

User · Answer

Is something like this what you re looking for  def write vars to file f    vars       for name  val in vars items            f write  quot  s    s n quot     name  repr val     Usage   gt  gt  gt  import sys  gt  gt  gt  write vars to file sys stdout  dict   one   1   two   2   dict     two   2   one   1

User · Answer

1  Make the dictionary   X     a   1    2  Write to a new file   file   open  X Data py    w   file write str X   file close     Lastly  in the file that you want the variable to be  read that file and make a new variable with the data from the data file   import ast file   open  X Data py    r   f   file read   file close   X   ast literal eval f

User · Answer

the repr function will return a string which is the exact definition of your dict  except for the order of the element  dicts are unordered in python   unfortunately  i can t tell a way to automatically get a string which represent the variable name    gt  gt  gt  dict     one   1   two   2   gt  gt  gt  repr dict     two   2   one   1     writing to a file is pretty standard stuff  like any other file write   f   open   file py    w    f write   dict       repr dict      n    f close

User · Answer

You can use pickle import pickle dict     one   1   two   2  file   open  dump txt    wb   pickle dump dict  file  file close    and to read it again file   open  dump txt    rb   dict   pickle load file   EDIT  Guess I misread your question  sorry     but pickle might help all the same

User · Answer

I found an easy way to get the dictionary value  and its name as well  I m not sure yet about reading it back  I m going to continue to do research and see if I can figure that out   Here is the code   your dict     one   1   two   2   variables    var for var in dir   if var 0 2          and var -1 -2            file   open  your file   w   for var in variables       if isinstance locals   var   dict             file write str var            str locals   var       n   file close     Only problem here is this will output every dictionary in your namespace to the file  maybe you can sort them out by values  locals   var     your dict for reference   You can also remove if isinstance locals   var   dict   to output EVERY variable in your namespace  regardless of type  Your output looks exactly like your decleration your dict     one   1   two   2    Hopefully this gets you one step closer  I ll make an edit if I can figure out how to read them back into the namespace     ---EDIT---  Got it  I ve added a few variables  and variable types  for proof of concept  Here is what my  testfile txt  looks like   string test   Hello World integer test   42 your dict     one   1   two   2    And here is the code the processes it   import ast  file   open  testfile txt    r   data   file readlines   file close    for line in data      var name  var val   line split            for possible num types in range 3      Range is the    number of types we will try casting to         try              var val   int var val              break         except  TypeError  ValueError               try                  var val   ast literal eval var val                  break             except  TypeError  ValueError  SyntaxError                   var val   str var val  replace   n                      break     locals   var name    var val   print  string test     string test       Type     type string test   print  integer test     integer test       Type     type integer test   print  your dict     your dict       Type     type your dict     This is what that outputs   string test   Hello World     Type    lt class  str  gt  integer test   42     Type    lt class  int  gt  your dict     two   2   one   1      Type    lt class  dict  gt    I really don t like how the casting here works  the try-except block is bulky and ugly  Even worse  you cannot accept just any type  You have to know what you are expecting to take in  This wouldn t be nearly as bad if you only cared about dictionaries  but I really wanted something a bit more universal   If anybody knows how to better cast these input vars I would LOVE to hear about it   Regardless  this should still get you there  D I hope I ve helped out

User · Answer

Do you just want to know how to write a line to a file  First  you need to open the file   f   open  filename txt    w     Then  you need to write the string to the file   f write  dict     one   1   two   2       n     You can repeat this for each line  the    n  adds a newline if you want it     Finally  you need to close the file   f close     You can also be slightly more clever and use with   with open  filename txt    w   as f     f write  dict     one   1   two   2       n          repeat for all desired lines   This will automatically close the file  even if exceptions are raised   But I suspect this is not what you are asking

[python] Write variable to file, including name

Examples related to python