[Python知识库]python dict学习笔记2 json与dict转换

代码简单明了, 在python 2.7中运行

代码

# coding=utf-8
# This is a sample Python script.


# Press the green button in the gutter to run the script.
import json
import traceback

if __name__ == '__main__':
    key1 = "key1"
    key2 = "key2"

    dict1 = {key1: 123, key2: "v2"}
    dict2 = {"all_params": dict1}
    jsonStr1 = json.dumps(dict2["all_params"])
    print "originalDict:%s, json str1:%s" % (dict2["all_params"], jsonStr1)
    print "\n"

    dict2["param_values"] = json.dumps([dict2["all_params"]])
    dict2["param_values2"] = dict2["all_params"]
    print "add param_values(value is json str) and param_values2(value is a dict) to dict"
    print "dict2:%s" % dict2
    print "\n"

    print 'dict2["param_values"] is str and is json array str, it can be converted into dict'
    # 'param_values': '[{"key2": "v2", "key1": 123}]'， tmp为list类型
    tmp1 = json.loads(dict2["param_values"])
    print "tmp1 Type:%s" % type(tmp1)
    valueFromJsonKeyOne1 = tmp1[0]
    print "valueFromJsonKeyOne1:%s" % valueFromJsonKeyOne1
    print "\n"

    print 'dict2["param_values2"] is not str and it is a json, it can\'t be converted into dict'
    # 'param_values2': {'key2': 'v2', 'key1': 123}， 不是json string，json.loads会报错：TypeError: expected string or buffer
    try:
        tmp2 = json.loads(dict2["param_values2"])
        print "tmp2 Type:%s" % type(tmp2)
        print "tmp2:%s" % tmp2
        print "\n"
    except Exception as ex:
        # 返回字符串类型，只给出异常信息，不包括异常信息的类型
        print'when converting json, ex:', ex
        print 'traceback.format_exc():\n%s' % traceback.format_exc()

    dict3 = {}
    dict3.update(valueFromJsonKeyOne1)
    print "new_dict is empty, update new_dict by valueFromJsonKeyOne"
    print "new_dict:%s" % dict3
    for k, v in dict3.items():
        print "%s:%s" % (k, v)

    print "jsonStr1 is json str, it can be converted into dict"
    # jsonStr1为'{"key2": "v2", "key1": 123}'， 因此tmpDict2是dict类型
    tmpDict2 = json.loads(jsonStr1)
    print "tmpDict2:%s" % tmpDict2
    print "tmpDict2[0]:%s" % tmpDict2[0]
    print "\n"

    print "done"

调试结果

运行结果

Traceback (most recent call last):
  File "/Users/ericyang/PycharmProjects/pythonProject/jsonmap.py", line 56, in <module>
    print "tmpDict2[0]:%s" % tmpDict2[0]
KeyError: 0
originalDict:{'key2': 'v2', 'key1': 123}, json str1:{"key2": "v2", "key1": 123}


add param_values(value is json str) and param_values2(value is a dict) to dict
dict2:{'param_values': '[{"key2": "v2", "key1": 123}]', 'all_params': {'key2': 'v2', 'key1': 123}, 'param_values2': {'key2': 'v2', 'key1': 123}}


dict2["param_values"] is str and is json array str, it can be converted into dict
tmp1 Type:<type 'list'>
valueFromJsonKeyOne1:{u'key2': u'v2', u'key1': 123}


dict2["param_values2"] is not str and it is a json, it can't be converted into dict
when converting json, ex: expected string or buffer
traceback.format_exc():
Traceback (most recent call last):
  File "/Users/ericyang/PycharmProjects/pythonProject/jsonmap.py", line 36, in <module>
    tmp2 = json.loads(dict2["param_values2"])
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 339, in loads
    return _default_decoder.decode(s)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/decoder.py", line 364, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
TypeError: expected string or buffer

new_dict is empty, update new_dict by valueFromJsonKeyOne
new_dict:{u'key2': u'v2', u'key1': 123}
key2:v2
key1:123
jsonStr1 is json str, it can be converted into dict
tmpDict2:{u'key2': u'v2', u'key1': 123}

Process finished with exit code 1