javascript - 在javascript中将NaN转换为0(Convert NaN to 0 in javascript)

Question

Is there a way to convert NaN values to 0 without an if statement:(没有if语句，有没有办法将NaN值转换为0：)

if (isNaN(a)) a = 0; It is very annoying to check my variables every time.(每次检查我的变量都非常烦人。)   ask by Tamás Pap translate from so

Answer 1

You can do this:(你可以这样做：)

a = a || 0 ...which will convert a from any "falsey" value to 0 .(...这会将a的任何“ falsey”值转换为0 。) The "falsey" values are:(“假”值是：) false null undefined 0 "" ^{( empty string )}("" ^{（空字符串）}) NaN ^{( Not a Number )}(NaN ^{（不是数字）}) Or this if you prefer:(如果您愿意，也可以这样：) a = a ? a : 0; ...which will have the same effect as above.(...将具有与上述相同的效果。) If the intent was to test for more than just NaN , then you can do the same, but do a toNumber conversion first.(如果要测试的不仅仅是NaN ，则可以执行相同的操作，但首先进行toNumber转换。) a = +a || 0 This uses the unary + operator to try to convert a to a number.(这使用一元+运算符尝试将a转换为数字。) This has the added benefit of converting things like numeric strings '123' to a number.(这具有将数字字符串'123'转换为数字的附加好处。) The only unexpected thing may be if someone passes an Array that can successfully be converted to a number:(唯一出乎意料的事情是，如果有人传递了可以成功转换为数字的数组：) +['123'] // 123 Here we have an Array that has a single member that is a numeric string.(在这里，我们有一个具有单个成员的数组，该成员是数字字符串。) It will be successfully converted to a number.(它将成功转换为数字。)