1.将一串数字每三位用逗号分隔
function formatNum(str){ var newStr = ""; var count = 0; if(str.indexOf(".")==-1){ for(var i=str.length-1;i>=0;i--){ if(count % 3 == 0 && count != 0){
newStr = str.charAt(i) + "," + newStr;
}else{
newStr = str.charAt(i) + newStr;
}
count++;
}
str = newStr + ".00"; //自动补小数点后两位
console.log(str)
}else{ for(var i = str.indexOf(".")-1;i>=0;i--){// 4
// console.log('newStr:',newStr)
if(count % 3 == 0 && count != 0){
newStr = str.charAt(i) + "," + newStr; // console.log('i:',i)
// console.log('str.charAt(i):',str.charAt(i))
// console.log('newStr:',newStr)
// console.log('newStr:',newStr)
}else{
newStr = str.charAt(i) + newStr; //逐个字符相接起来
}
count++;
} console.log('newStr:',newStr) console.log('str:',newStr +(str+'00')) console.log((str + "00").indexOf("."))
str = newStr + (str + "00").substr((str + "00").indexOf("."),3); console.log(str)
}
}
formatNum('13213.24'); //输出13,213.34formatNum('132134.2'); //输出132,134.20formatNum('132134'); //输出132,134.00formatNum('132134.236'); //输出132,134.232.将一串数字每四位用空格分隔
//方法1：function formatNum(str){ var array1 = str.split(''),
array2 = []; for(var i = 0; i < array1.length; i++){ if(i != 0 && i % 4 === 0){
array2.push(' ');
array2.push(array1[i]);
}else{
array2.push(array1[i]);
}
}
console.log(array2.join(''))
}
formatNum('132134484321882')//方法2：function formatNum(str){ var array = str.split(''); var count = 0; for(var i = 0; i <= array.length; i++){ if(i != 0 && i == 4){ array.splice(i,0,' ');
} if(i > 4 && i % 4 == 0){
count += 5; if(count != 5){ array.splice(count-1,0,' ');
}
}
}
console.log(array.join(''))
}
formatNum('132134484321882123143545412341231254642365768')
作者：饥人谷_米弥轮
链接：https://www.jianshu.com/p/c50890735195
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