python requests post多层字典

pyhton requests模块post方法传参为多层字典时，转换错误，
如，表单传参
{
“a”:1,
“b”:{
“A”:2,
“B”:3
}
}

post请求后看到form data是：
a:1
b:A
b:B

• 
  
• 查看官方文档：
  

More complicated POST requests
Typically, you want to send some form-encoded data — much like an HTML form. To do this, simply pass a dictionary to the data argument. Your dictionary of data will automatically be form-encoded when the request is made:

payload = {‘key1’: ‘value1’, ‘key2’: ‘value2’}

r = requests.post(“http://httpbin.org/post“, data=payload)
print(r.text)
{
…
“form”: {
“key2”: “value2”,
“key1”: “value1”
},
…
}

这里说post传入的dict类型参数会被自动转化为form-encoded，查看请求后，这里的demo是一个一层的字典。多层字典传输的时候，确实会异常。

解决办法：

将第二层字典转化为json，json.dumps({“A”:2,”B”:3})，然后赋给b。