Javascript 检查 JSON 对象中是否存在值
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Check whether a value exists in JSON object
提问by Ivan
I have the next JSON:
我有下一个 JSON：
var JSONObject = {"animals": [{name:"cat"}, {name:"dog"}]};
What is the best way to know if the "dog" value exists in the JSON object?
了解 JSON 对象中是否存在“狗”值的最佳方法是什么？
Thanks.
谢谢。
Solution 1
解决方案1
var JSONObject = {"animals": [{name:"cat"}, {name:"dog"}]};
...
for (i=0; i < JSONObject.animals.length; i++) {
if (JSONObject.animals[i].name == "dog")
return true;
}
return false;
Solution 2 (JQuery)
解决方案 2 (JQuery)
var JSONObject = {"animals": [{name:"cat"}, {name:"dog"}]};
...
$.map(JSONObject.animals, function(elem, index) {
if (elem.name == "dog")
return true;
});
return false;
Solution 3 (using some() method)
解决方案 3（使用 some() 方法）
function _isContains(json, value) {
let contains = false;
Object.keys(json).some(key => {
contains = typeof json[key] === 'object' ?
_isContains(json[key], value) : json[key] === value;
return contains;
});
return contains;
}
回答by Vijay Sirigiri
var JSON = [{"name":"cat"}, {"name":"dog"}];
The JSON variable refers to an array of object with one property called "name". I don't know of the best way but this is what I do?
JSON 变量指的是具有一个名为“name”的属性的对象数组。我不知道最好的方法，但这就是我所做的？
var hasMatch =false;
for (var index = 0; index < JSON.length; ++index) {
var animal = JSON[index];
if(animal.Name == "dog"){
hasMatch = true;
break;
}
}
回答by Gibolt
Check for a value single level
检查单个级别的值
const hasValue = Object.values(json).includes("bar");
Check for a value multi-level
检查多级值
function hasValueDeep(json, findValue) {
const values = Object.values(json);
let hasValue = values.includes(findValue);
values.forEach(function(value) {
if (typeof value === "object") {
hasValue = hasValue || hasValueDeep(value, findValue);
}
})
return hasValue;
}
回答by Ponmudi VN
Below function can be used to check for a value in any level in a JSON
下面的函数可用于检查 JSON 中任何级别的值
function _isContains(json, value) {
let contains = false;
Object.keys(json).some(key => {
contains = typeof json[key] === 'object' ? _isContains(json[key], value) : json[key] === value;
return contains;
});
return contains;
}
then to check if JSON contains the value
然后检查 JSON 是否包含该值
_isContains(JSONObject, "dog")
See this fiddle: https://jsfiddle.net/ponmudi/uykaacLw/
看到这个小提琴：https: //jsfiddle.net/ponmudi/uykaacLw/
Most of the answers mentioned here compares by 'name' key. But no need to care about the key, can just checks if JSON contains the given value. So that the function can be used to find any value irrespective of the key.
这里提到的大多数答案都是按“名称”键进行比较的。但无需关心密钥，只需检查 JSON 是否包含给定值即可。因此该函数可用于查找任何值，而不管键如何。
回答by solarbaypilot
You could improve on the answer from Ponmudi VN:
您可以改进Ponmudi VN 的答案：
- Shorter Code
- Look for a keyand a value
- 较短的代码
- 查找键和值
See this fiddle: https://jsfiddle.net/solarbaypilot/sn3wtea2/
看到这个小提琴：https: //jsfiddle.net/solarbaypilot/sn3wtea2/
function _isContains(json, keyname, value) {
return Object.keys(json).some(key => {
return typeof json[key] === 'object' ?
_isContains(json[key], keyname, value) : key === keyname && json[key] === value;
});
}
var JSONObject = {"animals": [{name:"cat"}, {name:"dog"}]};
document.getElementById('dog').innerHTML = _isContains(JSONObject, "name", "dog");
document.getElementById('puppy').innerHTML = _isContains(JSONObject, "name", "puppy");
回答by Diego Pereira
I think this is the best and easy way:
我认为这是最好的和简单的方法：
$lista = @()
$lista += ('{"name": "Diego" }' | ConvertFrom-Json)
$lista += ('{"name": "Monica" }' | ConvertFrom-Json)
$lista += ('{"name": "Celia" }' | ConvertFrom-Json)
$lista += ('{"name": "Quin" }' | ConvertFrom-Json)
if ("Diego" -in $lista.name) {
Write-Host "is in the list"
return $true
}
else {
Write-Host "not in the list"
return $false
}
回答by Kevin Bowersox
This example puts your JSON into proper format and does an existence check. I use jquery for convenience.
此示例将您的 JSON 放入正确的格式并进行存在检查。为方便起见，我使用 jquery。
<!-- HTML -->
<span id="test">Hello</span><br>
<span id="test2">Hello</span>
//Javascript
$(document).ready(function(){
var JSON = {"animals":[{"name":"cat"}, {"name":"dog"}]};
if(JSON.animals[1].name){
$("#test").html("It exists");
}
if(!JSON.animals[2]){
$("#test2").html("It doesn't exist");
}
});
回答by bchhun
iterate through the array and check its name value.
遍历数组并检查其名称值。
