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Copying Array Items Using slice()

rthefounding profile image Randy Rivera ・1 min read
  • The next method we will cover is slice(). Rather than modifying an array, slice() copies or extracts a given number of elements to a new array, leaving the array it is called upon untouched. slice() takes only 2 parameters — the first is the index at which to begin extraction, and the second is the index at which to stop extraction (extraction will occur up to, but not including the element at this index).
  • Ex:
function forecast(arr) {
 let todaysWeather = arr.slice(2, 4)
 return todaysWeather;
}

console.log(forecast(['cold', 'rainy', 'warm', 'sunny', 'cool', 'thunderstorms'])); will display ['warm', 'sunny']
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  • We defined a function, forecast, that takes an array as an argument. I modified the function using slice() to extract information from the argument array and return a new array that contains the string elements warm and sunny.
  • In effect, we have created a new array by extracting elements from an existing array.
  • Another Ex:
let weatherConditions = ['rain', 'snow', 'sleet', 'hail', 'clear'];

let todaysWeather = weatherConditions.slice(1, 3);
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  • todaysWeather would have the value ['snow', 'sleet'], while weatherConditions would still have ['rain', 'snow', 'sleet', 'hail', 'clear'].

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