Objective-c语言 字符串类NSMutableString用法

NSMutableString 是NSString 的子类，NSMutableString有很多方法，下面是总结的几种常用的方法：

stringWithString:，类级构造方法创建NSString对象；

insertString:，插入字符串，不会创建新的对象；

appendString:，追加字符串，不会创建新的对象；

deleteCharactersInRange:，在一个范围内删除字符串，不会创建新的对象；

replaceCharactersInRange: withString:，替换字符串，不会创建新的对象。

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
NSString *str1 = @"Objective C";
NSString *search,*replace;
NSMutableString *mstr;
NSRange substr;

//从不可变的字符创建可变字符串对象
mstr = [NSMutableString stringWithString: str1];
NSLog(@" %@", mstr);

//插入字符串
[mstr insertString: @ " Java" atIndex: 9];
NSLog(@" %@", mstr);
//具有连接效果的插入字符串
[mstr insertString: @ " and C++"atIndex: [mstr length]];
NSLog(@" %@", mstr);
//字符串连接方法
[mstr appendString: @ " and C"];
NSLog(@" %@", mstr);
//使用NSRange删除字符串
[mstr deleteCharactersInRange:NSMakeRange(16, 13)];
NSLog(@" %@", mstr);
//查找字符串位置
substr = [mstr rangeOfString: @ "string B and"];
if (substr.location != NSNotFound) {
[mstr deleteCharactersInRange: substr];
NSLog(@" %@", mstr);
}
//直接设置可变字符串

[mstr setString: @ "This is string A "];
NSLog(@" %@", mstr);

[mstr replaceCharactersInRange: NSMakeRange(8, 8)
withString: @ "a mutable string "];
NSLog(@" %@", mstr);
//查找和替换
search = @"This is ";
replace = @"An example of ";

substr = [mstr rangeOfString:search];

if (substr.location != NSNotFound) {
[mstr replaceCharactersInRange:substr withString: replace];
NSLog(@" %@", mstr);
}
//查找和替换所有的情况
search = @"a";
replace = @"X";
substr = [mstr rangeOfString: search];

while (substr.location != NSNotFound) {
[mstr replaceCharactersInRange:substr withString: replace];
substr = [mstr rangeOfString: search];
}
NSLog(@" %@", mstr);

[pool drain];
return 0;
}

运行结果如下：

2011-09-08 16:35:26.320 2.10.1-2[3124:a0f]  Objective C
2011-09-08 16:35:26.323 2.10.1-2[3124:a0f]  Objective Java C
2011-09-08 16:35:26.324 2.10.1-2[3124:a0f]  Objective Java C and C++
2011-09-08 16:35:26.324 2.10.1-2[3124:a0f]  Objective Java C and C++ and C
2011-09-08 16:35:26.325 2.10.1-2[3124:a0f]  Objective Java CC
2011-09-08 16:35:26.325 2.10.1-2[3124:a0f]  This is string A
2011-09-08 16:35:26.326 2.10.1-2[3124:a0f]  This is a mutable string
2011-09-08 16:35:26.326 2.10.1-2[3124:a0f]  An example of a mutable string
2011-09-08 16:35:26.327 2.10.1-2[3124:a0f]  An exXmple of X mutXble string

我们解释主要代码。语句[mstr deleteCharactersInRange:NSMakeRange(16, 13)]是删除指定范围的字符串，函数NSMakeRange 是创建NSRange结构体，其中第一个参数是位置，第二个参数是长度；语句[mstr replaceCharactersInRange: NSMakeRange(8, 8)withString: @ "a mutable string "]替换指定访问的字符串；语句[mstr deleteCharactersInRange:
substr]是删除指定范围的字符串。