cast-index.md

cast index

NAME

cast-index - Compute the storage slot location for an entry in a mapping.

SYNOPSIS

cast index key_type key slot

DESCRIPTION

Compute the storage slot location for an entry in a mapping.

Use cast storage to get the value.

OPTIONS

{{#include common-options.md}}

EXAMPLES

// World.sol

mapping (address => uint256) public mapping1;
mapping (string => string) public mapping2;

1. Compute the storage slot of an entry (hello) in a mapping of type mapping(string => string), located at slot 1:

   >> cast index string "hello" 1
   0x3556fc8e3c702d4479a1ab7928dd05d87508462a12f53307b5407c969223d1f8
   >> cast storage [address] 0x3556fc8e3c702d4479a1ab7928dd05d87508462a12f53307b5407c969223d1f8
   world

SEE ALSO

cast