使用json.dumps的目的是将python对象转化为字符串，再用json.loads转化为python对象

s = str([1,2])
print(s)
s = json.dumps([1,2])
print(s)
t = json.dumps([1, 2]) == str([1, 2])
print(t)
"""
[1, 2]
[1, 2]
True
"""

# str转化后的字符串中，引号是用单引号，而json.dumps是双引号，这在字典和列表中都是这样
s = str(['a', 'b'])
print(s)
s = json.dumps(['a', 'b'])
print(s)
t = json.dumps(['a', 'b']) == str(['a', 'b'])
print(t)
"""
['a', 'b']
["a", "b"]
False
"""

s = str({'a': 1})
print(s)
s = json.dumps({'a': 1})
print(s)
t = json.dumps({'a': 1}) == str({'a': 1})
print(t)
"""
{'a': 1}
{"a": 1}
False
"""

# str转化后的字符串中，True是首字母大写的，而json.dumps将所有字母都转化为了小写
s = str([True, False])
print(s)
s = json.dumps([True, False])
print(s)
t = json.dumps([True, False]) == str([True, False])
print(t)
"""
[True, False]
[true, false]
False
"""

# None：str转化后的字符串中，None还是用None表示，而json.dumps则用null表示
s = str([1, None])
print(s)
s = json.dumps([1, None])
print(s)
t = json.dumps([1, None]) == str([1, None])
print(t)
"""
[1, None]
[1, null]
False
"""

那么 json格式的str 使用dumps会是怎么样呢？

data = '{"A": "a", "B": 1, "C": null}'

a = json.loads(data)
print(a)
print(type(a))
"""
{'A': 'a', 'B': 1, 'C': None}
<class 'dict'>
"""

data = '{"A": "a", "B": 1, "C": null}'

a = json.dumps(data)
print(a)
print(type(a))
a = json.loads(a)
print(a)
print(type(a))
a = json.loads(a)
print(a)
print(type(a))
"""
"{\"A\": \"a\", \"B\": 1, \"C\": null}"
<class 'str'>
{"A": "a", "B": 1, "C": null}
<class 'str'>
{'A': 'a', 'B': 1, 'C': None}
<class 'dict'>
"""

其他

# str + str --> dict
data = '{"A": "B", "C": ${arg1}$, "D": null}'
arg = '{"aa": "11", "bb": "22"}'

data = re.sub(r'\${(.*?)}\$', str(arg), str(data), count=1)
l1 = json.loads(data)
print(l1)
print(type(l1))
"""
{'A': 'B', 'C': {'aa': '11', 'bb': '22'}, 'D': None}
<class 'dict'>
"""

# str + 对象dumps --> dict
data = '{"A": "B", "C": ${arg1}$, "D": null}'
arg = {"aa": "11", "bb": "22"}
arg = json.dumps(arg, ensure_ascii=False)
data = re.sub(r'\${(.*?)}\$', arg, data, count=1)
l2 = json.loads(data)
print(l2)
print(type(l2))
"""
{'A': 'B', 'C': {'aa': '11', 'bb': '22'}, 'D': None}
<class 'dict'>
"""

# str + (str->dumps)  --> dict
data = '{"A": "B", "C": "${arg1}$", "D": null}'
arg = "hello"

data = json.dumps(data, ensure_ascii=False)
data = re.sub(r'\${(.*?)}\$', arg, data, count=1)
l2 = json.loads(data)
print(type(l2))
l2 = json.loads(l2)
print(l2)
print(type(l2))
"""
<class 'str'>
{'A': 'B', 'C': 'hello', 'D': None}
<class 'dict'>
"""

参考：https://juejin.cn/post/6844903609499385869