Find index of any array using value in string array

Question

a=[
    {x:1,y:1,i:"Piechart1"},
    {x:2,y:1,i:"Piechart2"},
    {x:3,y:1,i:"Piechart3"}
]

str=["Piechart1","Piechart3"];

I want get index by comparing array string.Output in above example should be [0,2] Could you please let me know how to achieve in lodash ,javascript

Answer 1

将str中的每个值映射到a中的索引。

str.map((str) => a.findIndex((ele) => str === ele.i))

Answer 2

You can use reduce() method and includes() to check if element exists in another array.

 const a = [{"x":1,"y":1,"i":"Piechart1"},{"x":2,"y":1,"i":"Piechart2"},{"x":3,"y":1,"i":"Piechart3"}] const str = ["Piechart1", "Piechart3"]; const result = a.reduce((r, {i}, ind) => { return str.includes(i) && r.push(ind), r }, []) console.log(result) 

Answer 3

Use .map() to map the strings to their index, and .findIndex inside the .map() callback to locate the index of the object.

 var a = [{x:1,y:1,i:"Piechart1"},{x:2,y:1,i:"Piechart2"},{x:3,y:1,i:"Piechart3"}]; var str = ["Piechart1","Piechart3"]; var res = str.map(s => a.findIndex(o => oi == s)); console.log(res); 

You can chain .filter(idx => idx != -1) on the end if there's any chance of one of the strings not being in the main array.