做接口测试的时候，有时候须要对字符串、json串进行一些转换，可是总是得破费一些工夫，实质来说还是有可能是这几个办法的应用没有弄清楚。
@TOC
1、json.loads()
源码：
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. ``object_hook`` is an optional function that will be called with the result of any object literal decode (a ``dict``). The return value of ``object_hook`` will be used instead of the ``dict``. This feature can be used to implement custom decoders (e.g. JSON-RPC class hinting). ``object_pairs_hook`` is an optional function that will be called with the result of any object literal decoded with an ordered list of pairs. The return value of ``object_pairs_hook`` will be used instead of the ``dict``. This feature can be used to implement custom decoders. If ``object_hook`` is also defined, the ``object_pairs_hook`` takes priority. ``parse_float``, if specified, will be called with the string of every JSON float to be decoded. By default this is equivalent to float(num_str). This can be used to use another datatype or parser for JSON floats (e.g. decimal.Decimal). ``parse_int``, if specified, will be called with the string of every JSON int to be decoded. By default this is equivalent to int(num_str). This can be used to use another datatype or parser for JSON integers (e.g. float). ``parse_constant``, if specified, will be called with one of the following strings: -Infinity, Infinity, NaN. This can be used to raise an exception if invalid JSON numbers are encountered. To use a custom ``JSONDecoder`` subclass, specify it with the ``cls`` kwarg; otherwise ``JSONDecoder`` is used. The ``encoding`` argument is ignored and deprecated. """作用：
将json格局的数据转化为字典类型
示例：
# -*- coding:utf-8 -*-import jsonjson_str = '{"token":"dasgdhasdas", "status":0, "data":{"name":"admin", "password":123456}, "author":null}'json_dict = json.loads(json_str)print("====转之前====")print("type(json_str)", type(json_str))print(json_str)print("====转之后====")print("type(json_dict)", type(json_dict))print(json_dict)
阐明：
字符串里有个null，转了之后变成了None，曾经变成Python格局的需要了，然而这个时候咱们间接应用eval（）进行转的话，可能会报错，提醒‘null’没有定义，所以如果有布尔类型的字符串转字段时候应用loads（）、没有的话间接应用eval（）也能够
# -*- coding:utf-8 -*-import jsonjson_str = '{"token":"dasgdhasdas", "status":0, "data":{"name":"admin", "password":123456}, "author":null}'json_dict = json.loads(json_str)print("====转之前====")print("type(json_str)", type(json_str))print(json_str)print("====转之后====")print("type(json_dict)", type(json_dict))print(json_dict)json_eval = eval(json_str)2、json.load()
源码：
def load(fp, *, cls=None, object_hook=None, parse_float=None, parse_int=None, parse_constant=None, object_pairs_hook=None, **kw): """Deserialize ``fp`` (a ``.read()``-supporting file-like object containing a JSON document) to a Python object. ``object_hook`` is an optional function that will be called with the result of any object literal decode (a ``dict``). The return value of ``object_hook`` will be used instead of the ``dict``. This feature can be used to implement custom decoders (e.g. JSON-RPC class hinting). ``object_pairs_hook`` is an optional function that will be called with the result of any object literal decoded with an ordered list of pairs. The return value of ``object_pairs_hook`` will be used instead of the ``dict``. This feature can be used to implement custom decoders. If ``object_hook`` is also defined, the ``object_pairs_hook`` takes priority. To use a custom ``JSONDecoder`` subclass, specify it with the ``cls`` kwarg; otherwise ``JSONDecoder`` is used. """ 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)作用：
从文件中读取json类型的数据，并转化为字典类型
示例：
# -*- coding:utf-8 -*-import json# json_str = '{"token":"dasgdhasdas", "status":0, "data":{"name":"admin", "password":123456}, "author":null}'# 文件中内容和json_str是一样的with open("file_str.txt", mode="r", encoding="utf-8") as file: json_dict = json.load(file)print("====转之前====")print("type(file", type(file))print(file)print("====转之后====")print("type(json_dict)", type(json_dict))print(json_dict)3、json.dumps()
源码：
def dumps(obj, *, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, cls=None, indent=None, separators=None, default=None, sort_keys=False, **kw): """Serialize ``obj`` to a JSON formatted ``str``. If ``skipkeys`` is true then ``dict`` keys that are not basic types (``str``, ``int``, ``float``, ``bool``, ``None``) will be skipped instead of raising a ``TypeError``. If ``ensure_ascii`` is false, then the return value can contain non-ASCII characters if they appear in strings contained in ``obj``. Otherwise, all such characters are escaped in JSON strings. If ``check_circular`` is false, then the circular reference check for container types will be skipped and a circular reference will result in an ``OverflowError`` (or worse). If ``allow_nan`` is false, then it will be a ``ValueError`` to serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) in strict compliance of the JSON specification, instead of using the JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``). If ``indent`` is a non-negative integer, then JSON array elements and object members will be pretty-printed with that indent level. An indent level of 0 will only insert newlines. ``None`` is the most compact representation. If specified, ``separators`` should be an ``(item_separator, key_separator)`` tuple. The default is ``(', ', ': ')`` if *indent* is ``None`` and ``(',', ': ')`` otherwise. To get the most compact JSON representation, you should specify ``(',', ':')`` to eliminate whitespace. ``default(obj)`` is a function that should return a serializable version of obj or raise TypeError. The default simply raises TypeError. If *sort_keys* is true (default: ``False``), then the output of dictionaries will be sorted by key. To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the ``.default()`` method to serialize additional types), specify it with the ``cls`` kwarg; otherwise ``JSONEncoder`` is used. """作用：
将Python中特定类型进行字符串化操作，即转换为json格局的数据
示例：
# -*- coding:utf-8 -*-import jsonjson_dic = {"token":"dasgdhasdas", "status":0, "data":{"name":"隔壁老王", "password":123456}, "author":None}json_str = json.dumps(json_dic)json_str_str = str(json_dic)print("====转之前====")print("type(json_dic)", type(json_dic))print(json_dic)print("====转之后====")print("type(json_str)", type(json_str))print(json_str)print("====应用str====")print("type(json_str_str)", type(json_str_str))print(json_str_str)
阐明：
其实就相似于间接用str()进行强制转换，然而dumps（）转了之后，有中文的被编码了，那这个时候如果有中文的话，在转换的时候，加ensure_ascii=False，如下：
# -*- coding:utf-8 -*-import jsonjson_dic = {"token":"dasgdhasdas", "status":0, "data":{"name":"隔壁老王", "password":123456}, "author":None}json_str = json.dumps(json_dic)json_str_ensure_ascii = json.dumps(json_dic, ensure_ascii=False)json_str_str = str(json_dic)print("====转之前====")print("type(json_dic)", type(json_dic))print(json_dic)print("====转之后====")print("type(json_str)", type(json_str))print("type(json_str_ensure_ascii)", type(json_str_ensure_ascii))print(json_str_ensure_ascii)print(json_str)print("====应用str====")print("type(json_str_str)", type(json_str_str))print(json_str_str)4、json.dump()
源码：
在这里插入代码片def dump(obj, fp, *, skipkeys=False, ensure_ascii=True, check_circular=True, allow_nan=True, cls=None, indent=None, separators=None, default=None, sort_keys=False, **kw): """Serialize ``obj`` as a JSON formatted stream to ``fp`` (a ``.write()``-supporting file-like object). If ``skipkeys`` is true then ``dict`` keys that are not basic types (``str``, ``int``, ``float``, ``bool``, ``None``) will be skipped instead of raising a ``TypeError``. If ``ensure_ascii`` is false, then the strings written to ``fp`` can contain non-ASCII characters if they appear in strings contained in ``obj``. Otherwise, all such characters are escaped in JSON strings. If ``check_circular`` is false, then the circular reference check for container types will be skipped and a circular reference will result in an ``OverflowError`` (or worse). If ``allow_nan`` is false, then it will be a ``ValueError`` to serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) in strict compliance of the JSON specification, instead of using the JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``). If ``indent`` is a non-negative integer, then JSON array elements and object members will be pretty-printed with that indent level. An indent level of 0 will only insert newlines. ``None`` is the most compact representation. If specified, ``separators`` should be an ``(item_separator, key_separator)`` tuple. The default is ``(', ', ': ')`` if *indent* is ``None`` and ``(',', ': ')`` otherwise. To get the most compact JSON representation, you should specify ``(',', ':')`` to eliminate whitespace. ``default(obj)`` is a function that should return a serializable version of obj or raise TypeError. The default simply raises TypeError. If *sort_keys* is true (default: ``False``), then the output of dictionaries will be sorted by key. To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the ``.default()`` method to serialize additional types), specify it with the ``cls`` kwarg; otherwise ``JSONEncoder`` is used. """作用：
将字典类型转化为json字符串格局，写入到文件中
# -*- coding:utf-8 -*-import jsonjson_dic = {"token":"dasgdhasdas", "status":0, "data":{"name":"隔壁老王", "password":123456}, "author":None}with open("file.txt", mode="a", encoding="utf-8") as file: json.dump(json_dic, file, ensure_ascii=False, indent=2)5、eval（）
源码：
def eval(*args, **kwargs): # real signature unknown """ Evaluate the given source in the context of globals and locals. The source may be a string representing a Python expression or a code object as returned by compile(). The globals must be a dictionary and locals can be any mapping, defaulting to the current globals and locals. If only globals is given, locals defaults to it. """ pass作用：
eval() 函数用来执行一个字符串表达式，并返回表达式的值。
示例：
# -*- coding:utf-8 -*-import jsonjson_str = '{"token":"dasgdhasdas", "status":0, "data":{"name":"admin","password":123456}}'json_eval = eval(json_str)print("====转之前====")print("type(json_str)", type(json_str))print(json_str)print("====转之后====")print("type(json_eval )", type(json_eval ))print(json_eval)