xcode 仅替换 NSString 中子字符串的第一个实例
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Replace only the first instance of a substring in an NSString
提问by Eric Brotto
So if you have an NSString that goes:
所以如果你有一个 NSString ：
@"My blue car is bigger than my blue shoes or my blue bicycle";
I would like a method that replaces only the first instance of blue with green, to produce:
我想要一种仅用绿色替换蓝色的第一个实例的方法，以产生：
@"My green car is bigger than my blue shoes or my blue bicycle";
How does one do this?
如何做到这一点？
回答by Jonathan Grynspan
Assuming the following inputs:
假设以下输入：
NSString *myString = @"My blue car is bigger then my blue shoes or my blue bicycle";
NSString *original = @"blue";
NSString *replacement = @"green";
The algorithm is quite simple:
算法非常简单：
NSRange rOriginal = [myString rangeOfString:original];
if (NSNotFound != rOriginal.location) {
myString = [myString stringByReplacingCharactersInRange:rOriginal withString:replacement];
}
回答by Kevin Sabbe
SWIFT 3 and 4 UPDATE:
SWIFT 3 和 4 更新：
extension String
{
func stringByReplacingFirstOccurrenceOfString(
target: String, withString replaceString: String) -> String
{
if let range = self.range(of: target) {
return self.replacingCharacters(in: range, with: replaceString)
}
return self
}
}
回答by Luca Davanzo
In Swift is useful extends Stringin this way:
在 Swift 中，以这种方式扩展String很有用：
public extension String {
func stringByReplacingFirstOccurrenceOfString(target: String, withString replaceString: String) -> String {
if let range = self.rangeOfString(target) {
return self.stringByReplacingCharactersInRange(range, withString: replaceString)
}
return self
}
}
In this way you can call wherever:
通过这种方式，您可以在任何地方调用：
let s = "The red red cat".stringByReplacingFirstOccurrenceOfString("red", withString: "fat")
print(s) // "The fat red cat"
回答by Daniel Saidi
Swift 4 version:
斯威夫特 4 版本：
func replacingFirstOccurrence(of string: String, with replacement: String) -> String {
guard let range = self.range(of: string) else { return self }
return replacingCharacters(in: range, with: replacement)
}
回答by ullstrm
A more Swift'y version of the implementations posted here. This one matches the syntax replacingOccurrences(of:with:)in Swift 5.1
此处发布的实现的更 Swift 版本。这个匹配replacingOccurrences(of:with:)Swift 5.1中的语法
extension String {
func replacingFirstOccurrence(of target: String, with replacement: String) -> String {
guard let range = self.range(of: target) else { return self }
return self.replacingCharacters(in: range, with: replacement)
}
}
An example of usage:
用法示例：
let string = "I like bacon, please give me some more bacon!"
let newString = string.replacingFirstOccurrence(of: "bacon", with: "meat")
回答by Eugene
NSString *initialString = @"My blue car is bigger then my blue shoes or my blue bicycle";
NSRange range = [initialString rangeOfString:@"blue"];
NSString *replacedString = [initialString stringByReplacingCharactersInRange:range withString:@"green"];
NSLog(@"replacedString: %@", replacedString);
回答by Eugene
First locate the substring, and then make the replacement. Example :
首先定位子串，然后进行替换。例子 ：
NSString *aString = @"foo bar foo";
NSRange firstFooRange = [aString rangeOfString:@"foo"];
NSString *anotherString = [aString stringByReplacingOccurrencesOfString:@"foo"
withString:@"bar"
options:0
range:firstFooRange];
NSStringdocumentation.
NSString文档。
回答by Abo3atef
-(NSString*) replaceFirstOccuarnceFromString: (NSString*)input withOriginal:(NSString*) original AndReplacment:(NSString*)replacement
{
NSRange rOriginal = [input rangeOfString: original];
if (NSNotFound != rOriginal.location) {
input = [input
stringByReplacingCharactersInRange: rOriginal
withString: replacement];
}
return input;
}
