javascript 如何在javascript中将String变量转换为int？
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How to convert String variable to int in javascript?
提问by Sami
What is the correct way to convert value of String variable to int/numeric variable? Why is bcIntstill string and why does isNaNreturn true?
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仍然是字符串，为什么isNaN返回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
回答by Florian Margaine
parseIntreturns a number only if you pass it a number as first character.
parseInt仅当您将数字作为第一个字符传递给它时才返回数字。
Examples:
例子：
parseInt( 'a', 10 ); // NaN
parseInt( 'a10', 10 ); // NaN
parseInt( '10a', 10 ); // 10
parseInt( '', 10 ); // NaN
parseInt( '10', 10 ); // 10
Also, you may take a look at the +operator if you want to get strings that are only numbers.
此外，+如果您想获取只有数字的字符串，您可以查看运算符。
+'a'; // NaN
+'a10'; // NaN
+'10a'; // NaN
+''; // 0, that's tricky
+'10'; // 10
Edit: According to your comment, I've tested parseInt:
编辑：根据您的评论，我已经测试过parseInt：
parseInt( '08-20 19:41:02.880', 10 ); // 8
You're doing something else wrong. parseIntreturns everything till it's not a number. If the first isn't a number (or it doesn't find any number), it returns NaN.
你做错了其他事情。parseInt返回所有内容，直到它不是数字。如果第一个不是数字（或找不到任何数字），则返回NaN.
回答by Sami
The answer is that I used localStorage.setItem('bc',JSON.stringify(bc))and it added double quote to bcbecause it was in that case already a string and that's why parseIntwasn't working. Value was ""1"".
答案是我使用localStorage.setItem('bc',JSON.stringify(bc))并添加了双引号，bc因为在那种情况下它已经是一个字符串，这就是为什么parseInt不起作用。价值是""1""。
