如何在javascript中将String变量转换为int?
将String变量的值转换为int / numeric变量的正确方法是什么?为什么 bcInt
仍为字符串,为什么 isNaN
return true
?
What is the correct way to convert value of String variable to int/numeric variable? Why is bcInt
still string and why does isNaN
return true
?
bc=localStorage.getItem('bc');
var bcInt=parseInt(bc,10);
var bcInt2=1;
console.log("bc------------>" +bc +" isNaN:" +isNaN(bc)); //isNaN returns true
console.log("bcInt------------>" +bcInt +" isNaN:" +isNaN(bcInt)); //isNaN returns true
bcInt2// isNaN returns false
parseInt
只有在您将数字作为第一个字符传递时才返回一个数字。
parseInt
returns a number only if you pass it a number as first character.
示例:
parseInt( 'a', 10 ); // NaN
parseInt( 'a10', 10 ); // NaN
parseInt( '10a', 10 ); // 10
parseInt( '', 10 ); // NaN
parseInt( '10', 10 ); // 10
另外,你可以看一下 +
运算符如果你想获得只是数字的字符串。
Also, you may take a look at the +
operator if you want to get strings that are only numbers.
+'a'; // NaN
+'a10'; // NaN
+'10a'; // NaN
+''; // 0, that's tricky
+'10'; // 10
编辑:根据你的评论,我测试了 parseInt
:
According to your comment, I've tested parseInt
:
parseInt( '08-20 19:41:02.880', 10 ); // 8
你做错了什么。 parseInt
返回所有内容,直到它不是数字。如果第一个不是数字(或者没有找到任何数字),则返回 NaN
。
You're doing something else wrong. parseInt
returns everything till it's not a number. If the first isn't a number (or it doesn't find any number), it returns NaN
.