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- Store data in mapping vs. array 3 answers
So I was implementing a trading contract and need to keep a list of products on sale. I was using arrays but later switched to mappings.
So arrays implementation:
uint public productsOnSale; uint public totalProductsOnSale; // array of product to its position mapping(uint => uint) productToIndex;
while sale can be achieved using
uint public totalProductsOnSale; mapping(uint => uint) indextoProduct; mapping(uint => uint) productToIndex;
Since in case of arrays we keep track of values at any index, we can achieve that using mapping as well.
Are there any downsides of using mappings instead of an array? In terms of computation time or in terms of cost (gas)?