整整一年了。
数组要领
经由过程数组长度增加/删除末了一项
var arr = [1,2];
arr[arr.length] = 3; //arr = [1,2,3];
arr.length -= 1; //arr = [1];
经由过程join()
返回反复字符的字符串
var arr = new Array(7);
arr.join('6'); //666666
到场/掏出数组头尾的元素
var arr = [1,2];
arr.unshift(0); //3,arr = [0,1,2];
arr.push(3); //3,arr = [1,2,3];
arr.shift(); //1,arr = [2];
arr.pop(); //2,arr = [1];
倒序分列数组元素
var arr = ['xiaoming','xiaohong'];
arr.reverse(); //arr = ['xiaohong','xiaoming'];
sort()
排序
var arr = [9,5,0,1,39,61];
function compare(val1, val2) {
return val1 - val2;
}
arr.sort(compare); //[0, 1, 5, 9, 39, 61]
sort()
依据属性排序
var love = [{'name': 'xiaoming', 'age': 23, 'height': 167},{'name': 'xiaohua', 'age': 25, 'height': 165}];
function compareProperty(property) {
return function(obj1, obj2) {
return obj1[property] -obj2[property];
};
}
love.sort(compareProperty('age'));
console.log('岁数最小:' + love[0].name); //xiaoming
love.sort(compareProperty('height'));
console.log('身高最小:' + love[0].name); //xiaohua
操纵数组
var arr = [0,1,2,3];
arr.concat(4,[5,6]); //兼并数组
arr.slice(1,2); //提取数组
arr.splice(2,2); //删除第三项和第四项,删除的项以新数组返回
arr.splice(1,0,0.5); //插进去项,删除的项以新数组返回
查询字符索引
var arr = [9,5,0,1,3,9,6,1];
arr.indexOf(1,4);
arr.lastIndexOf(1);
迭代数组
var arr = [1,2,3,4,5,4,3,2,1];
var every = arr.every(function(item, index, array){
return (item > 2);
});
var some = arr.some(function(item, index, array){
return (item > 2);
});
var filter = arr.filter(function(item, index, array){
return (item > 2);
});
var map = arr.map(function(item, index, array){
return (item * 2);
});
console.log(every); //false 每一项都返回true则返回true
console.log(some); //true 有一项返回true则返回true
console.log(filter); //[3, 4, 5, 4, 3] 挑选返回true的项
console.log(map); //[2, 4, 6, 8, 10, 8, 6, 4, 2] 返回对每一项操纵后的数组
arr.forEach(function(item, index, array){ //对每一项举行操纵
console.log(item + ' : ' + index);
});
字符串要领
查询字符
'hiyohoo'.charAt(1); //i
'hiyohoo'.charCodeAt(1); //105
查询字符索引
'hiyohoo'.indexOf('o'); //3
'hiyohoo'.lastIndexOf('o'); //6
操纵字符串
'hiyohoo'.concat(' is ', 'NICE'); //hiyohoo is NICE
'hiyohoo'.slice(1, -1); //iyoho 首位和末位,能够截止到倒数位
'hiyohoo'.substr(1,5); //iyoho 首位和长度,第一位的负数加长度,第二位的负数变成零
'hiyohoo'.substring(6,1); //iyoho 首位和末位,负数悉数变成零,一二位依大小自动排序
转换字符串
' hiyohoo '.trim(); //hiyohoo
'HIYOHOO'.toLowerCase(); //hiyohoo
'hiyohoo'.toUpperCase(); //HIYOHOO
替代字符
'hiyohoo'.replace('oo', 'o'); //hiyoho
支解字符串
'hiyohoo'.split('o'); //["hiy", "h", "", ""]
转载请说明出处:https://segmentfault.com/a/1190000004615200
文章不定期更新完美,假如能对你有一点点启示,我将不胜幸运。