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for
var array = [1,2,3,4,5,6,7];
for (var i = 0; i < array.length; i) {
console.log(i,array[i]);
} for in
for(let index in array) {
console.log(index,array[index]);
};
var A = {a:1,b:2,c:3,d:"hello world"};
for(let k in A) {
console.log(k,A[k]);
}
forEach
array.forEach(v=>{
console.log(v);
});
array.forEach（function(v){
console.log(v);
});for of
for(let v of array) {
console.log(v);
};
let s = "helloabc";
for(let c of s) {
console.log(c);
}