---
id: 56533eb9ac21ba0edf2244d8
title: Comparisons with the Logical And Operator
challengeType: 1
videoUrl: ''
localeTitle: 与逻辑和运算符的比较
---
## Description
有时你需要一次测试多个东西。当且仅当其左侧和右侧的操作数为true时， 逻辑和运算符（ && ）才返回true。如果将if语句嵌套在另一个语句中，则可以实现相同的效果： if（num> 5）{
if（num <10）{
返回“是”;
}
}
返回“否”;
如果num大于5且小于10则仅返回“Yes”。相同的逻辑可以写成： if（num> 5 && num <10）{
返回“是”;
}
返回“否”;
## Instructions
将两个if语句合并为一个语句，如果val小于或等于50且大于或等于25 ，则返回"Yes" 。否则，将返回"No" 。
## Tests
```yml
tests:
- text: 你应该使用一次&&运算符
testString: assert(code.match(/&&/g).length === 1);
- text: 你应该只有一个if语句
testString: assert(code.match(/if/g).length === 1);
- text: testLogicalAnd(0)应返回“否”
testString: assert(testLogicalAnd(0) === "No");
- text: testLogicalAnd(24)应返回“否”
testString: assert(testLogicalAnd(24) === "No");
- text: testLogicalAnd(25)应返回“是”
testString: assert(testLogicalAnd(25) === "Yes");
- text: testLogicalAnd(30)应该返回“是”
testString: assert(testLogicalAnd(30) === "Yes");
- text: testLogicalAnd(50)应该返回“是”
testString: assert(testLogicalAnd(50) === "Yes");
- text: testLogicalAnd(51)应返回“否”
testString: assert(testLogicalAnd(51) === "No");
- text: testLogicalAnd(75)应返回“否”
testString: assert(testLogicalAnd(75) === "No");
- text: testLogicalAnd(80)应返回“否”
testString: assert(testLogicalAnd(80) === "No");
```
## Challenge Seed
```js
function testLogicalAnd(val) {
// Only change code below this line
if (val) {
if (val) {
return "Yes";
}
}
// Only change code above this line
return "No";
}
// Change this value to test
testLogicalAnd(10);
```
## Solution
```js
// solution required
```