blocks|key|442137|text|您需要先创建字符串。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|442138|NSMutableString+*teststring+=+[[NSMutableString+alloc]init];

[teststring+appendString:@"hey"];

NSLog(teststring);|code-block|syntax|javascript|442139|现在，它将打印出来。|442140|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|$]]

You need to create the string first.

<pre><code>NSMutableString *teststring = [[NSMutableString alloc]init];

[teststring appendString:@"hey"];

NSLog(teststring);
</code></pre>

Now, it will print.

blocks|key|656656|text|这一行|type|unstyled|depth|inlineStyleRanges|entityRanges|data|656657|NSMutableString+*teststring;|code-block|syntax|javascript|656658|简单地建立一个指针，但不创建任何东西。相反，您需要创建一个新的NSMutableString实例，例如：|offset|length|style|CODE|656659|NSMutableString+*teststring+=+[[NSMutableString+alloc]+init];
[teststring+appendString:@"hey"];
NSLog("%25@",+teststring);|656660|entityMap^0|0|0|V|F|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

This line

<pre><code>NSMutableString *teststring;
</code></pre>

simply establishes a pointer, but does not create anything. Instead, you need to create a new instance of <code>NSMutableString</code>, for example:

<pre><code>NSMutableString *teststring = [[NSMutableString alloc] init];
[teststring appendString:@"hey"];
NSLog("%@", teststring);
</code></pre>

blocks|key|656685|text|示例：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|656686|NSMutableString+*buffer+=+[[NSMutableString+alloc]+init];+//+retain+count+=+1.+Because+of+the+"alloc",+you+have+to+call+a+release+later

[buffer+appendString:@"abc"];
NSLog(@"1+:+%25@",+buffer);
[buffer+appendString:@"def"];
NSLog(@"2+:+%25@",+buffer);

[buffer+release];+//+retain+count+=+0+=>+delete+object+from+memory|code-block|syntax|javascript|656687|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|$]]

Sample:

<pre><code>NSMutableString *buffer = [[NSMutableString alloc] init]; // retain count = 1. Because of the "alloc", you have to call a release later

[buffer appendString:@"abc"];
NSLog(@"1 : %@", buffer);
[buffer appendString:@"def"];
NSLog(@"2 : %@", buffer);

[buffer release]; // retain count = 0 =&gt; delete object from memory
</code></pre>

blocks|key|656717|text|将第一行更改为|type|unstyled|depth|inlineStyleRanges|entityRanges|data|656718|NSMutableString+*teststring+=+[NSMutableString+string];|code-block|syntax|javascript|656719|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|$]]

Change first line to 

<pre><code>NSMutableString *teststring = [NSMutableString string];
</code></pre>

blocks|key|442242|text|NSMutableString+*tag+=+[NSMutableString+stringWithString:+@"hello+<td>+this+is+inside+td+</td>+000999+<><>+..<.+><>+00000+<td>uuuuu</td>+vvvvv+<td>+this+is+also+inside+td+</td>"];++
++++NSRange+open+=+[tag+rangeOfString:@"<"];+
++++while(open.location+!=+NSNotFound)+
++++{
++++++++NSRange+close+=+[tag+rangeOfString:@">"];+
++++++++NSRange+string+=+NSMakeRange(open.location,+close.location-open.location%2B1);
++++++++[tag+replaceCharactersInRange:string+withString:@""];+++++++++++++++
++++++++open+=++[tag+rangeOfString:@"<"];
++++++++NSLog(@"%25@",tag);
++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|442243|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>NSMutableString *tag = [NSMutableString stringWithString: @"hello &lt;td&gt; this is inside td &lt;/td&gt; 000999 &lt;&gt;&lt;&gt; ..&lt;. &gt;&lt;&gt; 00000 &lt;td&gt;uuuuu&lt;/td&gt; vvvvv &lt;td&gt; this is also inside td &lt;/td&gt;"]; 
 NSRange open = [tag rangeOfString:@"&lt;"]; 
 while(open.location != NSNotFound) 
 {
 NSRange close = [tag rangeOfString:@"&gt;"]; 
 NSRange string = NSMakeRange(open.location, close.location-open.location+1);
 [tag replaceCharactersInRange:string withString:@""]; 
 open = [tag rangeOfString:@"&lt;"];
 NSLog(@"%@",tag);
 }
</code></pre>

i'm an absolute newbie with objective-c

with this code

<pre><code>NSMutableString *teststring;
[teststring appendString:@"hey"];
NSLog(teststring);
</code></pre>

nothing gets displayed in the console.

Surely i'm doing something wrong here... :-)

How to append a string to NSMutableString

我绝对是objective-c的新手使用下面的代码NSMutableString *teststring;[teststring appendString:@"hey"];NSLog(teststring);控制台中不显示任何内容。我肯定做错了什么.:-)

问如何将字符串追加到NSMutableString
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何将字符串追加到NSMutableStringEN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问如何将字符串追加到NSMutableString
EN