What is Solidity mapping?
Overview
Mapping is identical to a dictionary in every other language. In Solidity, it’s a hash table that stores data as key-value pairs, with the key being any of the built-in data types but not reference types, and the value being any type. When it comes to Solidity and the Ethereum blockchain, mappings are most commonly used to link a unique Ethereum address to a corresponding value type.
What is mapping?
Any other variable type that accepts a key type and a value type is referred to as mapping.
Syntax
mapping(key => value) <access specifier> <name>;
Creating mapping
Example
A structure is defined and a mapping is made in the contract mapping example.
pragma solidity ^0.5.12;// Defining contractcontract mapping_sample {//Defining structurestruct worker{string worker;string duty;uint8 renumeration;}// Creating a mappingmapping (address => worker) result;address[] public worker_result;}
Code explanation
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In line 4, we define a contract.
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In lines 7-12, we define the structure for the worker.
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In line 15, we declare the different structure elements regarding the worker.
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In line 16, we create the mapping.
