js むずい
| ruby | node.js |
|---|---|
| File.read('file.txt') | const fs = require('fs') fs.readFileSync('file.txt', 'UTF-8') |
| File.write('file.txt', content) | fs.writeFileSync('file.txt', content) |
| a = [ 0, 1, 2, 3, 4, 5 ] a.delete_at(3) # => 3 a # =>[ 0, 1, 2, 4, 5 ] |
const a = [ 0, 1, 2, 3, 4, 5 ] a.splice(3, 1) // => [ 3 ] a // =>[ 0, 1, 2, 4, 5 ] |
| a = [ 0, 7, 2, 5, 9, 1 ] a.max # => 9 |
const a = [ 0, 7, 2, 5, 9, 1 ] Math.max(a) // => 9 |
| a = [ 1, 2, 3 ] a.each { |a| puts a } |
const a = [ 1, 2, 3 ] for(let m of a) { console.log(a) } |
| h = {a: 1, b: 2, c: 3} h.each { |k, v| puts v } |
const o = {a: 1, b: 2, c: 3} for(let k of Object.keys(o)) { console.log(o[k]) } |
| s = '123' s.to_i # => 123 |
const s = '123' parseInt(s, '10') // => 123 |
| o = {a: 1, b: 2, c: 3, d: 4, e: 5} pluck = [:a, :c, :e].map { |k| [k, o[k]] }.to_h # => {a: 1, c: 3, e: 5} |
const o = {a: 1, b: 2, c: 3, d: 4, e: 5} const pluck = (({a, c, e}) => ({a, c, e}))(o) // => {a: 1, c: 3, e: 5} |
| s = 'asdfasdf' s.gsub('df', 'DF') # => 'asDFasDF' |
const s = 'asdfasdf' s.replace(/df/g, 'DF') // => 'asDFasDF' |
| require 'YAML' y = YAML.load_file('a.yml') |
const fs = require('fs') const YAML = require('yaml') y = YAML.parse(fs.readFileSync('a.yml', 'utf8') |
| h = [{d: 3}, {d: 10}, {d: 12}] h.any? { |r| 9 < r[:d] } # => true |
const o = [{d: 3}, {d: 10}, {d: 12}] o.some((r) => (9 < r.d)) // => true |
| a = [{d: 30}, {d: 10}, {d: 3}] index = a.index { |r| r[:d] == 3 } # => 2 |
const a = [{d: 30}, {d: 10}, {d: 3}] const index = a.findIndex(r => r.d === 3) // => 2 |
| val = 'AAA' "embed#{val}value" # => 'embedAAAvalue' |
const val = 'AAA' `embed${val}value` // => 'embedAAAvalue' |
| a = [1, 2, 3] b = ['a', 'b', 'c'] zip = a.zip(b) # => [[1, 'a'], [2, 'b'], [3, 'c']] |
const a = [1, 2, 3] const b = ['a', 'b', 'c'] const zip = a.map((e, i) => [e, b[i]]) // => [[1, 'a'], [2, 'b'], [3, 'c']] |
| a = ['a', 'b', 'c'] mapped = a.map { |m| m * 2 } # => ['aa', 'bb', 'cc'] |
const a = ['a', 'b', 'c'] const mapped = a.map(m => (m + m)) // => ['aa', 'bb', 'cc'] |
| a = [1, 2, 3] sum = a.reduce(0) do |memo, cur| memo += cur memo end # => 6 |
const a = [1, 2, 3] const sum = a.reduce((memo, cur) => { memo += cur return memo }, 0) // => 6 |
| a = ['a', 'bb', 'c', 'ddd', 'e'] selected = a.select { |m| m.length == 1 } # => ['a', 'c', 'e'] |
const a = ['a', 'bb', 'c', 'ddd', 'e'] const selected = a.filter(m => (m.length === 1)) // => ['a', 'c', 'e'] |
| a = ['a', 'b', 'c'] a.map.with_index { |m, idx| "#{m}-#{idx}" } # => ["a-0", "b-1", "c-3"] |
const a = ['a', 'b', 'c'] a.map((m, idx) => (m + '-' + idx;)) // => ["a-0", "b-1", "c-3"] |
| a = [1, 2, 3] a.clear a # => [] |
const a = [1, 2, 3] a.length = 0 a // => [] |
| a = [] a.empty? # => true |
const a = [] a.length === 0 // => true |
| a = [1, 2, 3] a.shift # => 1 a.unshift 5 # => [5, 2, 3] a.pop # => 3 a << 6 # => [5, 2, 6] |
const a = [1, 2, 3] a.shift() // => 1 a.unshift(5) a.pop() // => 3 a.push(6) a // => [5, 2, 6] |
| a = [1, 2, 3] a.find { |m| 1 < m } # => 2 |
const a = [1, 2, 3] a.find(m => (1 < m) } // => 2 |
| a = [1, 2, 3] a.all? { |m| 0 < m } # => true |
const a = [1, 2, 3] a.every(m => (0 < m)) // => true |
つど調べたら追記!!
- Array.splice(https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/Array/splice)
var arrDeletedItems = array.splice(start[, deleteCount[, item1[, item2[, ...]]]])