blocks|key|457552|text|实际上有两种选择；|type|unstyled|depth|inlineStyleRanges|entityRanges|data|457553|由于NSString是只读的，您需要在NSString上调用mutableCopy来获取一个实际可以更改的NSMutableString，然后在NSMutableString上调用replaceCharactersInRange:withString:来替换其中的字符。如果您想多次更改字符串，这会更有效率。|offset|length|style|CODE|457554|NSString上还有一个stringByReplacingCharactersInRange:withString:方法，它返回一个替换了字符的新NSString。这对于单个更改可能更有效，但要求您为每个替换项创建一个新的NSString。|457555|entityMap^0|0|U|B|2I|10|0|D|1A|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@$D|N|E|O|F|G]|$D|P|E|Q|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|R|8|@$D|S|E|T|F|G]]|9|@]|A|$]]|$1|J|3|-4|5|6|7|U|8|@]|9|@]|A|$]]]|K|$]]

There are really two options;

Since NSString is read-only, you need to call <code>mutableCopy</code> on the NSString to get an NSMutableString that can actually be changed, then call <code>replaceCharactersInRange:withString:</code> on the NSMutableString to replace the characters in it. This is more efficient if you want to change the string more than once.

There is also a <code>stringByReplacingCharactersInRange:withString:</code> method on NSString that returns a new NSString with the characters replaced. This may be more efficient for a single change, but requires you to create a new NSString for each replacement.

blocks|key|457584|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|457585|NSString+*str+=+@"*******";
str+=+[str+stringByReplacingCharactersInRange:NSMakeRange(3,+1)+withString:@"A"];
NSLog(@"%25@",str);|code-block|syntax|javascript|457586|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try with this:

<pre><code>NSString *str = @"*******";
str = [str stringByReplacingCharactersInRange:NSMakeRange(3, 1) withString:@"A"];
NSLog(@"%@",str);
</code></pre>

blocks|key|457681|text|如果您不介意使用一点C语言，可以使用下面这样的内容：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|457682|char+*str+=+(char+*)[myString+UTF8String];
str[2]+=+'A';
myString+=+[NSString+stringWithUTF8String:str];|code-block|syntax|javascript|457683|当然，在执行此操作之前，您应该绝对确保myString至少包含3个字符。除此之外，这是一种非常快速和有效的方式来做这样的事情。|457684|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

If you don't mind using a little C, use something like this:

<pre><code>char *str = (char *)[myString UTF8String];
str[2] = 'A';
myString = [NSString stringWithUTF8String:str];
</code></pre>

Of course you should be absolutely sure that myString has at least 3 characters before doing this. Other than that, it's a very fast and efficient way to do something like this.

blocks|key|457744|text|尝试此示例方法|type|unstyled|depth|inlineStyleRanges|entityRanges|data|457745|-(NSString+*)string:(NSString*)string+ByReplacingACharacterAtIndex:(int)i+byCharacter:(NSString*)StringContainingAChar{

++++return+[string+stringByReplacingCharactersInRange:NSMakeRange(i,+1)+withString:StringContainingAChar];

}|code-block|syntax|javascript|457746|如果您的字符串是“than”，并且您希望将第一个字符"t“替换为"*”，则调用方法|457747|[self+string:yourString+ByReplacingACharacterAtIndex:0+byCharacter:@"*"]|457748|快跑快走|457749|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Try this sample method

<pre><code>-(NSString *)string:(NSString*)string ByReplacingACharacterAtIndex:(int)i byCharacter:(NSString*)StringContainingAChar{

 return [string stringByReplacingCharactersInRange:NSMakeRange(i, 1) withString:StringContainingAChar];

}
</code></pre>

if your string is "testing" and you want first character "t" should be replaced with "*" than call method 

<pre><code>[self string:yourString ByReplacingACharacterAtIndex:0 byCharacter:@"*"]
</code></pre>

Run and Go

blocks|key|457927|text|我的贡献来自于响应的快速扩展：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|457928|extension+NSString{

++++func+replacingACharacterAtIndex(pIndex+:+Int,+pChar+:+Character)+->+NSString{

++++++++return+self.stringByReplacingCharactersInRange(NSRange(location:+pIndex,+length:+1),+withString:+String(pChar))
++++}
}|code-block|syntax|javascript|457929|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

My contribution with a swift extension from the response :

<pre><code>extension NSString{

 func replacingACharacterAtIndex(pIndex : Int, pChar : Character) -&gt; NSString{

 return self.stringByReplacingCharactersInRange(NSRange(location: pIndex, length: 1), withString: String(pChar))
 }
}
</code></pre>

I'm looking for a way to replace a character at a certain index of a NSString. 

For example: <code>myString = @"******";</code>

I want to replace the 3rd " * " with an "A", so that the string looks like this: <code>myString = @"**A***";</code>

How can I achieve this?

Thanks in advance

Replace a character at a certain index in NSString

我正在寻找一种方法来替换某个NSString索引处的字符。例如：myString = @"******";我想用"A“替换第三个”*“，这样字符串看起来就像这样：myString = @"**A***";我如何才能做到这一点？提前感谢

问替换NSString中某个索引处的字符
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