What is the difference between json load and json loads functions

Question

In Python  what is the difference between json load   and json loads     I guess that the load   function must be used with a file object  I need thus to use a context manager  while the loads   function take the path to the file as a string  It is a bit confusing   Does the letter  s  in json loads   stand for string   Thanks a lot for your answers

User · Answer

The json load   method  without  s  in  load   can read a file directly   import json with open  strings json   as f      d   json load f      print d    json loads   method  which is used for string arguments only   import json  person      name    Bob    languages     English    Fench     print type person     Output    lt type  str  gt   person dict   json loads person  print  person dict    Output    name    Bob    languages     English    Fench     print type person dict     Output    lt type  dict  gt     Here   we can see after using loads   takes a string   type str    as a input and return dictionary

User · Answer

Yes  s stands for string  The json loads function does not take the file path  but the file contents as a string  Look at the documentation at https   docs python org 2 library json html

User · Answer

Just going to add a simple example to what everyone has explained   json load    json load can deserialize a file itself i e  it accepts a file object  for example     open a json file for reading and print content using json load with open   xyz json data json    r   as content    print json load content     will output    u event    u id   u 5206c7e2-da67-42da-9341-6ea403c632c7   u name   u Sufiyan Ghori      If I use json loads to open a file instead     you cannot use json loads on file object with open  json data json    r   as content    print json loads content     I would get this error      TypeError  expected string or buffer   json loads    json loads   deserialize string   So in order to use json loads I will have to pass the content of the file using read   function  for example   using content read   with json loads   return content of the file   with open  json data json    r   as content    print json loads content read       Output    u event    u id   u 5206c7e2-da67-42da-9341-6ea403c632c7   u name   u Sufiyan Ghori      That s because type of content read   is string  i e   lt type  str  gt   If I use json load   with content read    I will get error   with open  json data json    r   as content    print json load content read       Gives      AttributeError   str  object has no attribute  read    So  now you know json load deserialze file and json loads deserialize a string   Another example   sys stdin return file object  so if i do print json load sys stdin    I will get actual json data   cat json data json     test py   u event    u id   u 5206c7e2-da67-42da-9341-6ea403c632c7   u name   u Sufiyan Ghori      If I want to use json loads    I would do print json loads sys stdin read     instead

User · Answer

QUICK ANSWER  very simplified       json load   takes a FILE      json load   expects a file  file object  - e g  a file you opened before given by filepath like  files example json          json loads   takes a STRING      json loads   expects a  valid  JSON string - i e    foo    bar        EXAMPLES     Assuming you have a file example json with this content     key 1   1   key 2    foo    Key 3   null      gt  gt  gt  import json  gt  gt  gt  file   open  example json     gt  gt  gt  type file   lt class   io TextIOWrapper  gt    gt  gt  gt  file  lt  io TextIOWrapper name  example json  mode  r  encoding  UTF-8  gt    gt  gt  gt  json load file    key 1   1   key 2    foo    Key 3   None    gt  gt  gt  json loads file  Traceback  most recent call last     File   usr local python Versions 3 7 lib python3 7 json   init   py   line 341  in loads TypeError  the JSON object must be str  bytes or bytearray  not TextIOWrapper    gt  gt  gt  string      foo    bar      gt  gt  gt  type string   lt class  str  gt    gt  gt  gt  string    foo    bar      gt  gt  gt  json loads string    foo    bar     gt  gt  gt  json load string  Traceback  most recent call last     File   usr local python Versions 3 7 lib python3 7 json   init   py   line 293  in load     return loads fp read    AttributeError   str  object has no attribute  read

User · Answer

Documentation is quite clear  https   docs python org 2 library json html  json load fp   encoding   cls   object hook   parse float   parse int   parse constant   object pairs hook     kw               Deserialize fp  a  read  -supporting file-like object containing a   JSON document  to a Python object using this conversion table    json loads s   encoding   cls   object hook   parse float   parse int   parse constant   object pairs hook     kw               Deserialize s  a str or unicode instance containing a JSON document    to a Python object using this conversion table    So load is for a file  loads for a string

User · Answer

In python3 7 7  the definition of json load is as below according to cpython source code   def load fp     cls None  object hook None  parse float None          parse int None  parse constant None  object pairs hook None    kw        return loads fp read            cls cls  object hook object hook          parse float parse float  parse int parse int          parse constant parse constant  object pairs hook object pairs hook    kw    json load actually calls json loads and use fp read   as the first argument   So if your code is   with open  file  as fp      s   fp read       json loads s    It s the same to do this   with open  file  as fp      json load fp    But if you need to specify the bytes reading from the file as like fp read 10  or the string bytes you want to deserialize is not from file  you should use json loads    As for json loads    it not only deserialize string but also bytes  If s is bytes or bytearray  it will be decoded to string first  You can also find it in the source code   def loads s     encoding None  cls None  object hook None  parse float None          parse int None  parse constant None  object pairs hook None    kw          Deserialize   s    a   str      bytes   or   bytearray   instance     containing a JSON document  to a Python object                        if isinstance s  str           if s startswith   ufeff                raise JSONDecodeError  Unexpected UTF-8 BOM  decode using utf-8-sig                                      s  0      else          if not isinstance s   bytes  bytearray                raise TypeError f the JSON object must be str  bytes or bytearray                                f not  s   class     name              s   s decode detect encoding s    surrogatepass

[python] What is the difference between json.load() and json.loads() functions

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