Convert a python dict to a string and back

Question

I am writing a program that stores data in a dictionary object  but this data needs to be saved at some point during the program execution and loaded back into the dictionary object when the program is run again  How would I convert a dictionary object into a string that can be written to a file and loaded back into a dictionary object  This will hopefully support dictionaries containing dictionaries

User · Answer

If your dictionary isn t too big maybe str   eval can do the work   dict1     one  1   two  2   three     three 1   3 1   three 2   3 2    str1   str dict1   dict2   eval str1   print dict1  dict2   You can use ast literal eval instead of eval for additional security if the source is untrusted

User · Answer

I think you should consider using the shelve module which provides persistent file-backed dictionary-like objects  It s easy to use in place of a  real  dictionary because it almost transparently provides your program with something that can be used just like a dictionary  without the need to explicitly convert it to a string and then write to a file  or vice-versa     The main difference is needing to initially open   it before first use and then close   it when you re done  and possibly sync  ing it  depending on the writeback option being used   Any  shelf  file objects create can contain regular dictionaries as values  allowing them to be logically nested   Here s a trivial example   import shelve  shelf   shelve open  mydata      open for reading and writing  creating if nec shelf update   one  1   two  2   three     three 1   3 1   three 2   3 2     shelf close    shelf   shelve open  mydata   print shelf shelf close     Output     three     three 1   3 1   three 2   3 2    two   2   one   1

User · Answer

I use yaml for that if needs to be readable  neither JSON nor XML are that IMHO   or if reading is not necessary I use pickle   Write  from pickle import dumps  loads x   dict a 1  b 2  y   dict c   x  z 3  res   dumps y  open   var tmp dump txt    w   write res    Read back  from pickle import dumps  loads rev   loads open   var tmp dump txt   read    print rev

User · Answer

The json module is a good solution here  It has the advantages over pickle that it only produces plain text output  and is cross-platform and cross-version   import json json dumps dict

User · Answer

I use json   import json    convert to string input   json dumps   id   id       load to dict my dict   json loads input

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If in Chinses  import codecs fout   codecs open  xxx json    w    utf-8   dict to json   json dumps   text        ensure ascii False indent 2  fout write dict to json     n

User · Answer

Use the pickle module to save it to disk and load later on

User · Answer

Why not to use Python 3 s inbuilt ast library s function literal eval  It is better to use literal eval instead of eval  import ast str of dict      key1    key1value    key2    key2value    ast literal eval str of dict    will give output as actual Dictionary    key1    key1value    key2    key2value     And If you are asking to convert a Dictionary to a String then  How about using str   method of Python    Suppose the dictionary is     my dict     key1    key1value    key2    key2value     And this will be done like this     str my dict    Will Print        key1    key1value    key2    key2value      This is the easy as you like

User · Answer

Convert dictionary into JSON  string   import json   mydict      name     Don               surname     Mandol               age    43    result   json dumps mydict   print result 0 20     will get you        name    Don    sur   Convert string into dictionary  back to mydict   json loads result

User · Answer

If you care about the speed use ujson  UltraJSON   which has the same API as json   import ujson ujson dumps    key    value    81  True         key   value   81 true   ujson loads       key    value    81  true          u key   u value    81  True

[python] Convert a python dict to a string and back

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