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Javascript - The definitive guide - David Flanagan - Arrays Chapter
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| /** | |
| * Theory: | |
| -Arrays in JavaScript are an ordered collection of values | |
| -Its elements are untyped, an array can contain different types of data | |
| -Arrays are 32-bit indexed so its index can be from 0-4294967294 (2^32 - 2) | |
| and its elements can go from 0 to 4.294.967.295 | |
| */ | |
| /** | |
| * Relevant Examples | |
| */ | |
| // Dynamic Sizing | |
| let names = ["Anibal", "Peter"] | |
| console.log(names.length) // 2 | |
| names[10] = "Lucas" | |
| console.log(names.length) // 11 | |
| //Creating arrays | |
| let literalArray = [1,2,3] | |
| let spreadOperatorArrays = [...literalArray] // copy of [1,2,3] | |
| let arrayConstructor = new Array() | |
| let arrayOf = Array.of(1,2,3) // [1,2,3] | |
| let arrayFrom = Array.from(literalArray) // copy of [1,2,3] | |
| // Creating and Updating at the same time | |
| let rankings = [0, 100, 40, 20, 40, 343, 32, 22] | |
| let copy = Array.from(rankings, (r) => r % 10 === 0 ? r : 0) | |
| console.log(copy) // [0, 100, 40, 20, 40, 0, 0, 0] | |
| // Some and Every | |
| let yearTemperature = [40, 44, 40, 34, 30, 28, 26, 25, 28, 39, 35, 38] | |
| console.log(yearTemperature.some((temp) => temp > 40)) // There is at least one element over 40 degrees | |
| console.log(yearTemperature.every((temp) => temp % 2)) // false - not every number is mod 2 | |
| // Find and FindIndex | |
| let yearTemperature = [40, 44, 40, 34, 30, 28, 26, 25, 28, 39, 35, 38] | |
| console.log(yearTemperature.find((temp) => temp === 40)) // 40 the first value | |
| console.log(yearTemperature.findIndex((temp) => temp === 40)) // 0 the first encountered | |
| /* End*/ |
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