CODEWITHSUNDEEP
arraysjsonif-statementreact-nativelodash
Laney Williams
Laney Williams

Reputation: 593

How to find if one of the items in a JSON data is equal to one of the values in an array?

I have found and tried out .includes to help with this problem. But .includes did not work as I intended. It actually did find one item in the JSON that matched the value in the other array, but it only matched similar values:

result_postid array:

[10,22,12,36,45,206]

item.id from JSON data:

[{"id":"5","username":"Mike"},{"id":"13","username":"Tom"},{"id":"28","username":"Jake"},{"id":"136","username":"Josie"},{"id":"400","username":"Bill"},{"id":"538","username":"Sam"}]

I tried to figure out why some of the values kept returning true when they should be clearly false. Then I came to the conclusion that .includes was actually taking 36 from result_postid and matching it with 136 in item.id. This is how I setup the if statement with .includes:

{result_postid.includes(item.id) ?
 <Text>True</Text>
 :
 <Text>False</Text>
}

This is the result:

result_postid | item.id | Result

10 != 5,13,28,136,400,538: False
22 != 5,13,28,136,400,538: False
12 != 5,13,28,136,400,538: False
36 =  5,13,28,136,400,538: True <--- this should be false
45 != 5,13,28,136,400,538: False
206 != 5,13,28,136,400,538: False

Then I tried this attempt with Lodash: 

{_.intersection(item.id, result_postid) ?
<Text>True</Text>
 :
 <Text>False</Text>
}

And the results all came true, which is not correct:

10 = 5,13,28,136,400,538: True
22 = 5,13,28,136,400,538: True
12 = 5,13,28,136,400,538: True
36 = 5,13,28,136,400,538: True 
45 = 5,13,28,136,400,538: True
206 = 5,13,28,136,400,538: True

Is it possible to even compare values in an array to JSON data and show whether one value equal each other, if so true? If not, false?

Upvotes: 1

Views: 206

Answers (1)

Akrion
Akrion

Reputation: 18515

Here is a way to get the results you want. Since you are comparing strings to integers your results are not as what you would expect.

var data = [{"id":"5","username":"Mike"},{"id":"13","username":"Tom"},{"id":"28","username":"Jake"},{"id":"136","username":"Josie"},{"id":"400","username":"Bill"},{"id":"538","username":"Sam"}]

var arr = [10,22,12,36,45,206]

console.log(data.map(({id}) => arr.includes(+id)))
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>

By doing the +id you are converting the string to number before the next operation.

Upvotes: 1

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