Question

我想从数组中删除除第0个索引的数组元素

之外的所有元素

["a", "b", "c", "d", "e", "f"]

输出应为a

Answer 1

您可以设置数组的0) Desktop 1) Documents 2) Downloads 3) Music 4) Pictures 5) Public 6) Templates 7) XXX 8) Videos 9) backup_XXXX 10) dna 11) scripting 12) sessions 13) sh 14) temp属性。

length

或，使用splice(startIndex)方法

var input = ['a','b','c','d','e','f'];  
input.length = 1;
console.log(input);

Answer 2

这是head函数。 tail也被证明是一种免费功能。

注意，您只应在已知长度 1 或更多的数组上使用head和tail。

// head :: [a] -> a
const head = ([x,...xs]) => x;

// tail :: [a] -> [a]
const tail = ([x,...xs]) => xs;

let input = ['a','b','c','d','e','f'];

console.log(head(input)); // => 'a'
console.log(tail(input)); // => ['b','c','d','e','f']

Answer 3

如果您想将其保留在array中，可以使用slice或splice。或者再次包装wirst条目。

＆＃13;

var Input = ["a","b","c","d","e","f"];  

console.log( [Input[0]] );
console.log( Input.slice(0, 1) );
console.log( Input.splice(0, 1) );

＆＃13;

Answer 4

array = [a,b,c,d,e,f];
remaining = array[0];
array = [remaining];

Answer 5

您可以使用拼接来实现此目的。

Input.splice(0, 1);

这里有更多细节。。。http://www.w3schools.com/jsref/jsref_splice.asp

Answer 6

您可以使用切片：

var input =['a','b','c','d','e','f'];  
input = input.slice(0,1);
console.log(input);

文档：https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Array/slice

Answer 7

let request:NSMutableURLRequest = NSMutableURLRequest(URL:url)
request.HTTPMethod = "PATCH"
request.addValue("\(token)", forHTTPHeaderField: "authorization")
request.addValue("application/json", forHTTPHeaderField: "Content-Type")

do{
    let bodyData = try NSJSONSerialization.dataWithJSONObject(["email":"nuv@gmail.com"], options: [])
    request.HTTPBody = bodyData
    NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue())
    {
        (response, data, error) in
        if let mdata = data {
            let contents = NSString(data:data, encoding:NSUTF8StringEncoding)
            print(contents)
        } else {
            print(error?.localizedDescription)
        }
        }
}catch{
    print("failed serialization")
}

如果您想在某些约束条件下进行过滤，它会打印出第一个元素

var output=Input[0]

Answer 8

var input = ["a", "b", "c", "d", "e", "f"];

[input[0]];

// ["a"]

如何从javascript中除第一个之外的数组中删除所有元素

8 个答案: