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Start your free trialJoe Mbome
Front End Web Development Techdegree Graduate 17,250 PointsphoneNumbers is array of 10 digit phone numbers, where the first three digits, in parentheses, are area codes. Using red
not sure how to go about this
const phoneNumbers = ["(503) 123-4567", "(646) 123-4567", "(503) 987-6543", "(503) 234-5678", "(212) 123-4567", "(416) 123-4567"];
let numberOf503;
// numberOf503 should be: 3
// Write your code below
numberOf503= phoneNumbers.reduce((acc,number)=>number.substr(0,2)===503, 0);
1 Answer
Blake Larson
13,014 PointsThe substring
function will return a string so you want to compare it to "503"
. substring(1, 4)
gets the 3 numbers between the parentheses. Pretty sure this will pass this challenge.
numberOf503 = phoneNumbers.reduce((acc, number) => {
if(number.substring(1, 4) === "503") {
acc++
}
return acc;
} , 0);
I would definitely use filter
for something like this though when you get to use what you want. Just easier to use and cleaner. That would be like this in future scenarios.
numberOf503 = phoneNumbers.filter((number) => number.substring(1, 4) === "503").length;