NSString和NSMutableNSString的基本用法

 

 

 

//
//  main.m
//  NSString
/**
    NSString
    1.NSString 是一个不可以变的字符串对象
    2.NSMutableString是一个可变字符串。
 　　下面代码为字符串的：增、删、替换、查方法得演示。
 
 */
#import <Foundation/Foundation.h>
void MutableNSString(){
    NSMutableString *mutableString  =[NSMutableString stringWithFormat:@"我是可变字符串"];
    //指定位置增加字符串
    [mutableString insertString:@"增加" atIndex:([mutableString length])];
    NSLog(@"%@",mutableString);
    
    //指定范围替换全部字符串
    [mutableString replaceCharactersInRange:NSMakeRange(0, [mutableString length]) withString:@"替换后得字符串"];
    NSLog(@"%@",mutableString);
    NSRange rang  = [mutableString rangeOfString:@"字符串"];
    [mutableString replaceCharactersInRange:rang withString:@"string"];
    NSLog(@"%@",mutableString);
    //重新设置可变字符串内容
    [mutableString setString:@"ABCDAa"];
    //将A替换成E，方式为区分大小
    [mutableString replaceOccurrencesOfString:@"A" withString:@"E" options:NSLiteralSearch range:NSMakeRange(0, [mutableString length])];
    NSLog(@"%@",mutableString);
    //删除指定范围得字符串
    NSRange deleteRang =  [mutableString rangeOfString:@"a"];
    //删除前最好判断是否存在,或者使用@try捕捉异常
    [mutableString deleteCharactersInRange:deleteRang];
    
    NSLog(@"%@",mutableString);
}
void BaseStringMeth(){
    //字符串的基本方法
    NSString *str1  =  @"hello NSString ";
    //查询字符串得长度
    NSUInteger length=  [str1 length];
    NSLog(@"length = %lu",length);
    // 转换大写
    NSString *upperNSString = [str1 uppercaseString];
    NSLog(@"%@",upperNSString);
    //转换小写
    NSString *lowerNSString = [str1 lowercaseString];
    NSLog(@"%@",lowerNSString);
    //字符换链接
    NSString *appendString  = @"study ";
    NSString *afterAppendString = [appendString stringByAppendingString:str1];
    NSLog(@"%@",afterAppendString);
    //判断字符串是否相等
    NSString *a = @"string a";
    NSString *b = @"string b";
    NSString *c = @"string a";
    NSString *d = @"String a";
    NSString *e = @"Strina a";
    if([a isEqualToString:b] != YES){
        NSLog(@"不相等");
    }
    if([a isEqualToString:c]){
        NSLog(@"相等");
    }
    // 这个判断是严格区分大小写
    if([a isEqualToString:d]){
        NSLog(@"相等");
    }
    //字符串比较大小，字符串得比较其实就是比较
    NSString *compare1= @"1";
    NSString *compare2 = @"2";
    //- (NSComparisonResult)compare:(NSString *)string; 比较方法返回值是NSComparisonResult,他是一个枚举类型
    //typedef NS_ENUM(NSInteger, NSComparisonResult) {NSOrderedAscending = -1L, NSOrderedSame, NSOrderedDescending};
    if([compare1 compare:compare2] == NSOrderedAscending ){
        NSLog(@"compare1 <compare2");
    }else if ([compare1 compare:compare2] == NSOrderedSame ){
        NSLog(@"compare1 ==compare2");
    }else if ([compare1 compare:compare2] == NSOrderedDescending){
        NSLog(@"compare1 >compare2");
    }
    
    NSString *compare3= @"res1";
    NSString *compare4 = @"RES1";
    if([compare3 compare:compare4] == NSOrderedAscending ){
        NSLog(@"compare3 <compare4");
    }else if ([compare3 compare:compare4] == NSOrderedSame ){
        NSLog(@"compare3 ==compare4");
    }else if ([compare3 compare:compare4] == NSOrderedDescending){
        NSLog(@"compare3 >compare4");
    }
    //忽略大小写的比较
    if([compare3 caseInsensitiveCompare:compare4] == NSOrderedAscending ){
        NSLog(@"compare3 <compare4");
    }else if ([compare3 caseInsensitiveCompare:compare4] == NSOrderedSame ){
        NSLog(@"compare3 ==compare4");
    }else if ([compare3 caseInsensitiveCompare:compare4] == NSOrderedDescending){
        NSLog(@"compare3 >compare4");
    }
    
    
}
void NSStringSearch(){
    //字符串的查找
    NSString *str1  =  @"hello NSString ";
    NSString *hello = @"hello";
    //查找hello字符串的位置
    NSRange helloRang = [str1 rangeOfString:hello];
    NSLog(@"hello location=%lu and length=%lu",helloRang.location,helloRang.length);
    
    NSString *hello2 = @"hello2";
    NSRange helloRang2 = [str1 rangeOfString:hello2];
    //找不到对应的字符串的时候系统会返回一个NSNotFound
    if(helloRang2.location  == NSNotFound){
        NSLog(@"在%@,中没有找到对应的字符串%@",str1,hello2);
    }
    /**
     传入 NSStringCompareOptions 枚举的值
     enum{
     NSCaseInsensitiveSearch = 1,//不区分大小写比较
     NSLiteralSearch = 2,//区分大小写比较
     NSBackwardsSearch = 4,//从字符串末尾开始搜索
     NSAnchoredSearch = 8,//搜索限制范围的字符串
     NSNumbericSearch = 64//按照字符串里的数字为依据，算出顺序。例如 Foo2.txt < Foo7.txt < Foo25.txt
     //以下定义高于 mac os 10.5 或者高于 iphone 2.0 可用
     NSDiacriticInsensitiveSearch = 128,//忽略 "-" 符号的比较
     NSWidthInsensitiveSearch = 256,//忽略字符串的长度，比较出结果
     NSForcedOrderingSearch = 512//忽略不区分大小写比较的选项，并强制返回 NSOrderedAscending 或者 NSOrderedDescending
     //以下定义高于 iphone 3.2 可用
     NSRegularExpressionSearch = 1024//只能应用于 rangeOfString:..., stringByReplacingOccurrencesOfString:...和 replaceOccurrencesOfString:... 方法。使用通用兼容的比较方法，如果设置此项，可以去掉 NSCaseInsensitiveSearch 和 NSAnchoredSearch
     }
     
     */
    //指定范围进行查找。我们可以通过options来确定查询得方式。从头开始还是从尾开始
    NSRange nsstringRang= [str1 rangeOfString:@"NSString" options:NSCaseInsensitiveSearch range:NSMakeRange(0, [str1 length])];
    NSLog(@"location=%lu,length=%lu",nsstringRang.location,nsstringRang.length);
    
    
}

//字符串的截取
void SubString(){
    //字符串截取
    NSString *str1  =  @"hello NSString ";
    
    //从第5个字符开始截取到最后
    NSString *subString = [str1 substringFromIndex:5];
    NSLog(@"%@",subString);//输出NSString
    NSRange rang = {0,5};
    //指定范围得截取
    NSString *subByRang = [str1 substringWithRange:rang];
    NSLog(@"%@",subByRang);//输出hello
    //从0开始截取到指定的位置
    NSString *subToPosition= [str1 substringToIndex:5];
    NSLog(@"%@",subToPosition);//输出hello
}
//字符串的创建
void CreateNSString(){
    //字符串的创建
    NSString *str1 = @"hello NSString ";
    //静态方法创建字符串,
    NSString *str2 = [NSString stringWithFormat:@"NSString%i",2];
    //动态创建字符串,由于动态创建计数器会+1因此我们需要自己释放，str3初始化时没有相应的值
    NSString *str3 = [[NSString alloc]init];
    
    NSLog(@"%@",str3);
    [str3 release];
    
}


int main(int argc, const char * argv[]) {
    @autoreleasepool {
        CreateNSString();
        BaseStringMeth();
        SubString();
        NSStringSearch;
        MutableNSString();

    }
    return 0;
}