ios 在 Swift 中追加字符串

Append String in Swift

提问by PREMKUMAR

I am new to iOS. I am currently studying iOS using Objective-C and Swift.

我是 iOS 新手。我目前正在使用 Objective-C 和 Swift 学习 iOS。

To append a string in Objective-C I am using following code:

要在 Objective-C 中附加一个字符串，我使用以下代码：

 NSString *string1 = @"This is";
 NSString *string2 = @"Swift Language";
 NSString *appendString=[NSString stringWithFormat:@"%@ %@",string1,string2];
 NSLog(@"APPEND STRING:%@",appendString);

Anyone please guide me.

任何人请指导我。

回答by PREMKUMAR

Its very simple:

它非常简单：

For ObjC:

对于 ObjC：

     NSString *string1 = @"This is";
     NSString *string2 = @"Swift Language";

ForSwift:

ForSwift：

    let string1 = "This is"
    let string2 = "Swift Language"

For ObjC AppendString:

对于 ObjC AppendString：

     NSString *appendString=[NSString stringWithFormat:@"%@ %@",string1,string2];

For Swift AppendString:

对于 Swift AppendString：

    var appendString1 = "\(string1) \(string2)"
    var appendString2 = string1+string2

Result:

结果：

    print("APPEND STRING 1:\(appendString1)")
    print("APPEND STRING 2:\(appendString2)")

Complete Code In Swift:

Swift 中的完整代码：

    let string1 = "This is"
    let string2 = "Swift Language"
    var appendString = "\(string1) \(string2)"
    var appendString1 = string1+string2
    print("APPEND STRING1:\(appendString1)")
    print("APPEND STRING2:\(appendString2)")

回答by Isaac Drachman

In Swift, appending strings is as easy as:

在 Swift 中，附加字符串非常简单：

let stringA = "this is a string"
let stringB = "this is also a string"
let stringC = stringA + stringB

Or you can use string interpolation.

或者您可以使用字符串插值。

let stringC = "\(stringA) \(stringB)"

Notice there will now be whitespace between them.

请注意，它们之间现在会有空格。

Note: I see the other answers are using vara lot. The strings aren't changing and therefore should be declared using let. I know this is a small exercise, but it's good to get into the habit of best practices. Especially because that's a big feature of Swift.

注意：我看到其他答案正在使用var很多。字符串没有改变，因此应该使用let. 我知道这是一个小练习，但养成最佳实践的习惯是件好事。尤其是因为这是 Swift 的一大特色。

回答by Anbu.Karthik

let string2 = " there"
var instruction = "look over"

choice 1 :

选择1：

 instruction += string2;

  println(instruction)

choice 2:

选择2：

 var Str = instruction + string2;

 println(Str)

ref this

参考这个

回答by Esqarrouth

Add this extension somewhere:

在某处添加此扩展名：

extension String {
    mutating func addString(str: String) {
        self = self + str
    }
}

Then you can call it like:

然后你可以这样称呼它：

var str1 = "hi"
var str2 = " my name is"
str1.addString(str2)
println(str1) //hi my name is

A lot of good Swift extensions like this are in my repo here, check them out: https://github.com/goktugyil/EZSwiftExtensions

很多像这样的优秀 Swift 扩展都在我的仓库中，请查看：https: //github.com/goktugyil/EZSwiftExtensions

回答by Saurav Nagpal

You can simply append string like:

您可以简单地附加字符串，如：

var worldArg = "world is good"

worldArg += " to live";

回答by nicael

var string1 = "This is ";
var string2 = "Swift Language";
var appendString = string1 + string2;
println("APPEND STRING: \(appendString)");

回答by Shailendra Suriyal

According to Swift 4 Documentation, String values can be added together (or concatenated) with the addition operator (+) to create a new String value:

根据Swift 4 Documentation，可以使用加法运算符 (+) 将字符串值加在一起（或连接）以创建新的字符串值：

let string1 = "hello"
let string2 = " there"
var welcome = string1 + string2
// welcome now equals "hello there"

You can also append a String value to an existing String variable with the addition assignment operator (+=):

您还可以使用加法赋值运算符 (+=) 将字符串值附加到现有的字符串变量：

var instruction = "look over"
instruction += string2
// instruction now equals "look over there"

You can append a Character value to a String variable with the String type's append() method:

您可以使用 String 类型的 append() 方法将 Character 值附加到 String 变量：

let exclamationMark: Character = "!"
welcome.append(exclamationMark)
// welcome now equals "hello there!"

回答by Melvin

> Swift2.x:

> Swift2.x：

String("hello ").stringByAppendingString("world") // hello world

回答by Ilker Baltaci

SWIFT 2.x

斯威夫特 2.x

let extendedURLString = urlString.stringByAppendingString("&requireslogin=true")

SWIFT 3.0

斯威夫特 3.0

From Documentation: "You can append a Character value to a String variable with the String type's append() method:"so we cannot use append for Strings.

来自文档： “您可以使用 String 类型的 append() 方法将 Character 值附加到 String 变量：”因此我们不能对字符串使用 append。

urlString += "&requireslogin=true"

"+" Operator works in both versions

“+”运算符适用于两个版本

let extendedURLString = urlString+"&requireslogin=true"

回答by Paresh Hirpara

let firstname = "paresh"
let lastname = "hirpara"
let itsme = "\(firstname) \(lastname)"