任何使用一段 JavaScript 在两个字符串之间切换的方法？
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Any way to toggle between two strings using one piece of JavaScript?
提问by Bojangles
I want to do something like
我想做类似的事情
if(something.val() == 'string1')
{
something.val('string2');
}
else if(something.val() == 'string2')
{
something.val('string1')
}
But in one line of code. I can't quite remember how it's done, but it involves question marks and colons...
但是在一行代码中。我不太记得它是如何完成的，但它涉及问号和冒号......
回答by Matthew Manela
Try:
尝试：
something.val(something.val() == 'string1' ? 'string2' : 'string1');
It is called a ternary expression.
它被称为三元表达式。
回答by Cristian Sanchez
Look ma, no ternary operator!
看，没有三元运算符！
The following works because Javascript short circuits boolean expressions.
以下工作是因为 Javascript 短路布尔表达式。
If something == string1then evaluate string2-- since string2is a truthyvalue and the next expression involves the OR operation there is no need to continue. Stop and return string2.
如果something == string1然后评估string2- 因为string2是一个真值并且下一个表达式涉及 OR 操作，所以不需要继续。停下来返回string2。
If something !== string1then it will skip the next operand because if it is false, there is no point in evaluating the next operand (with AND). It will "jump" to the OR operation and return string1.
如果something !== string1然后它将跳过下一个操作数，因为如果它为假，则评估下一个操作数（使用 AND）就没有意义。它将“跳转”到 OR 操作并返回string1.
function toggleString(something, string1, string2) {
return something == string1 && string2 || string1;
}
something.val(toggleString(something.val(), "string1", "string2"));
If you want the assignment done:
如果你想完成任务：
function toggleValue(something, string1, string2) {
something.val(something.val() == string1 && string2 || string1);
}
toggleValue(something, "string1", "string2"); // something is a jQuery collection
In the end however, I would end up using the ternary operator because this solution might be unclear to other programmers. If you come from Java or other languages, you may expect the function to return a boolean because of all the boolean operators.
然而，最终我会使用三元运算符，因为其他程序员可能不清楚这个解决方案。如果您来自 Java 或其他语言，您可能希望函数返回一个布尔值，因为所有布尔运算符。
回答by kolossal7
Another way to do it using object properties:
另一种使用对象属性的方法：
{ 'string1': 'string2', 'string2': 'string1' }[value]
As in the question:
如问题所示：
something.val(
{ 'string1': 'string2', 'string2': 'string1' }[something.val()]
)
回答by Thierry
Though, the solutions with a ternary operator are the most readable, you could also use xor from Lodash:
虽然使用三元运算符的解决方案是最易读的，但您也可以使用 Lodash 的 xor：
x = _.xor([a, b], [x])[0]
For your specific case:
对于您的具体情况：
something.val(_.xor(['s1',?'s2'],?[something.val()])[0]);
回答by fehays
How about using @Daniel's code along with a jquery function:
如何将@Daniel 的代码与 jquery 函数一起使用：
$.fn.toggleVal = function (str1, str2) {
return this.val(this.val() == str1 && str2 || str1);
};
$("input").toggleVal('string 1', 'string 2');
回答by Eric
As of jQuery 1.4, you can do this:
从 jQuery 1.4 开始，您可以这样做：
something.val(function(index, val) {
return val == 'string1' ? 'string2' : 'string1';
});
回答by Mike Axiak
You mean to use the ternary operator:
您的意思是使用三元运算符：
something.val((something.val() == 'string1') ? 'string2' : 'string1');
回答by jcolebrand
something.val( something.val() == 'string1'? 'string2' : 'string1' );
or for clarification
或澄清
val astring = something.val() == 'string1'? 'string2' : 'string1';
something.val( astring );
回答by James Curran
something.val(something.val() == 'string1' ? 'string2' : 'string1');
