使用多个条件？ ：javascript中的语句

Question

需要检查三个条件并根据条件为变量赋值。

if(a =="z1"){
   b = "one";
} else if(a =="z2"){
   b = "two";
} else if(a =="z3"){
   b = "three";
}

是否可以在JavaScript中使用？ ：声明将其作为单行代码

Answer 1

是的，您可以将其转换为Conditional(ternary) operator。

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var a = "z3";
var b = a == "z1" ? "one" : a == "z2" ? "two" : a == "z3" ? "three" : "" ;

console.log(b);

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<小时/> 仅供参考：为了更好的可读性，我建议使用if...else语句或使用switch语句。虽然您需要对嵌套三元运算符使用括号，以避免在复杂操作的情况下出现问题。

Answer 2

var b = (a =="z1") ? "one" : ((a =="z2") ?"two":(a =="z3")?"three":null);

不要忘记阅读这篇文章很难阅读。 它可以用于一个if else块。

Answer 3

你可以这样做：

b =（a ==“z1”？“one”:( a ==“z2”？“two”:( a ==“z3”？“three”：undefined）））

Answer 4

var b = a == "z1" ? "one" : ( a == "z2" ? "two" : ( a == "z3" ? "three" : undefined ) ) ;

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a = "z1"

alert(a == "z1" ? "one" : ( a == "z2" ? "two" : ( a == "z3" ? "three" : undefined ) ) );

a = "z2"

alert(a == "z1" ? "one" : ( a == "z2" ? "two" : ( a == "z3" ? "three" : undefined ) ) );

a = "z3"

alert(a == "z1" ? "one" : ( a == "z2" ? "two" : ( a == "z3" ? "three" : undefined ) ) );

a = "z4"

alert(a == "z1" ? "one" : ( a == "z2" ? "two" : ( a == "z3" ? "three" : undefined ) ) );

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