- 如何在Array.forEach的循環裡break
- 【underscore.js 源碼解讀】for ... in 存在的浏覽器相容問題你造嗎
1. 數組
1.1 for i++
var arr = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
for (var i = 0, l = arr.length; i < l; i++) {
console.log(i, arr[i])
}
輸出:
1.2 for l--
var arr = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
for (var l = arr.length; l--;) {
console.log(l, arr[l])
}
輸出:
應用:
var arr = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
for (var l = arr.length; l--;) {
arr.splice(l, 1)
}
console.log(arr) // []
1.3 while l--
var arr = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
var l = arr.length
while(l--) {
console.log(l, arr[l])
}
2.對象
var obj = {one: 1, two: 2, three: 3}
for (var key in obj) {
console.log(key, obj[key])
}
輸出:
3. ES5
var arr = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
arr.forEach(function(value, index, array) {
console.log(index, value, array)
})
4. Underscore.js
<script src="underscore.js"></script>
<script>
var list = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
_.each(list, function(element, index, list) {
console.log(element, index, list, this)
}, list)
_.each({one: 1, two: 2, three: 3}, function(value, key, list) {
console.log(value, key, list)
})
</script>
5. jQuery
<script src="jquery-1.10.2.js"></script>
<script>
var list = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
$.each(list, function(index, value) {
console.log(index, value)
})
$.each({one: 1, two: 2, three: 3}, function(key, value) {
console.log(key, value)
})
</script>
6.Angular
angular.forEach(['a', 'b'], function(value, index) {
console.log(value, index)
})
angular.forEach({a: 1, b: 2}, function(value, key) {
console.log(value, key)
})
7.Python
python list周遊
info = ['a','b','c','d','ee','fff']
for m in info:
print m
for in
for in 循環
Object.prototype.bar = 1
var foo = {goo: undefined}
for (var p in foo) {
console.log(p) // goo bar
if (foo.hasOwnProperty(p)) {
console.log('hasOwnProperty', p) // goo
}
}