如何将字符串（类似于json）转换为json对象？

Question

 if(i!=0):
     json_str+=str({"tag_namespace": "dba_inops", "tag_key": "db_schema", "tag_value": "" + schema_arr.pop(i) + ""},)+","
     machine_arr.pop(i);
     #print json_str
 else:
     json_str+=str({"tag_namespace": "dba_inops", "tag_key": "db_schema", "tag_value": "" + schema_arr.pop(i) + ""})
     new_machine=machine_arr.pop(i);
     print json_str;

SO OUTPUT json_string is like :

{'tag_key': 'db_schema', 'tag_namespace': 'dba_inops', 'tag_value': 'xyz'}

BUT :-

new_tagmap.map=[json_str]
print new_tagmap.map;

when I try to put that constructed json_str into an array I get double quotes after the array bracket which is an invalid json.

["{'tag_key': 'db_schema', 'tag_namespace': 'dba_inops', 'tag_value': 'xyz'}"]

and if I do a replace of first and last char it replaces the {.

Is there a way to convert such a string to json, so that I can directly load it into the array as a json object without the "".

Still not able to add some thing like this :-

    {'tag_namespace': 'dba_inops', 'tag_key': 'db_name', 'tag_value': 'hi' },
    {'tag_namespace': 'dba_inops', 'tag_key': 'db_name', 'tag_value': 'abc' }

it says

raise ValueError(errmsg("Extra data", s, end, len(s))) ValueError: Extra data: line 1 column 77 - line 1 column 78 (char 77 - 78) bcoz of the , between the two lists when I do a loads().

Answer 1

I recommend using Python's built in json parser. Here is the documentation for it . You can use json.loads to create the structure, and use json.dumps to decode it. The link has many easy-to-follow examples.

If you want to add or change the object then you should do so in its Python representation. So, for example, let's say I load the following JSON string:

>>> x = json.loads('{ "animals": ["cat", "dog", "fish"], "numbers": [1, 2, 3], "people": ["joe", "sally", "beth"] }')

It creates a Python dictionary. Each entry in the dictionary contains a list of things:

>>> x
 {u'animals': [u'cat', u'dog', u'fish'],
 u'numbers': [1, 2, 3],
 u'people': [u'joe', u'sally', u'beth']}

Now let's imagine I want to add "mouse" to the list of animals. I can do so with Python's list append function, directly using Python code. No string manipulation required! This is much nicer and cleaner.

x['animals'].append("mouse")

Now let's turn that Python object back into JSON. Behold!

>>> my_new_json_string = json.dumps(x)
>>> print my_new_json_string
{"animals": ["cat", "dog", "fish", "mouse"], "numbers": [1, 2, 3], "people": ["joe", "sally", "beth"]}