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This article is to share with you about the difference between dictionary and json in Python development. The editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

What is the difference between dictionary and json in Python development? Dictionary is a data structure, json is a form of data representation, dictionary key value can only be hash, json must be a string.

Conceptual differences between dictionary and json in Python development:

I. Dictionary

Dictionary is a data structure, while json is a data format, the format will have some formal restrictions, such as json format requires and can only use double quotation marks as key or value boundary symbols (values can not be added double quotation marks if the value is a number), can not use single quotation marks, using single quotation marks or not using quotation marks will cause data reading errors, and "key" must use boundary characters (double quotation marks) But dictionaries don't matter. You can use either single or double quotation marks.

Dict is a complete data structure, an implementation of the data structure of Hash Table, and a set of encapsulated schemes from storage to extraction. It uses the built-in hash function to plan the storage location of key corresponding to value, so as to obtain O (1) data reading speed.

II. Json

Json is the acronym of JavaScript Object Notation, which literally means javascript object representation. Json refers to a data format object similar to javascript object. At present, this data format is more popular and gradually replaces the traditional xml data format. When the front end uses ajax, the data format returned by the front end is in json format.

Json is a data format that is a pure string. Can be parsed into dict or other forms of Python.

III. Difference and comparison between json and dict

The key of json can only be a string, and the dict of python can be any hash object (hashtable type)

The key of json can be ordered and repeated; the key of dict cannot be repeated.

The value of json can only be a string, floating point, Boolean, or null, or an array or object made up of them.

Json any key has a default value undefined,dict has no default value

The json access method can be [] or. The value of in and of;dict can only be accessed by subscript.

Json strings force double quotation marks. Dict strings can be in single or double quotation marks.

Dict can be nested with only arrays in tuple,json.

Json:true 、 false 、 null

Python:True 、 False 、 None

Json Chinese must be unicode encoded, such as "\ u6211".

The type of json is a string, and the type of dictionary is a dictionary.

IV. Hashtable

An object is hashtable when its hash value does not change during the declaration period and can be compared with other objects.

1. The basic types in python are all Hashtable, such as str, bytes, numeric type, tuple, etc.

2. User-defined types default to hashtable, because their hash value is the id () value.

3. Frozenset is always hashtable, because all of their projects are defined as hashtable

4. Tuple is hashtable only if all the items in tuple are hashtable.

These are the differences between dictionaries and json in Python development. The editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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