OC之NSString、NSMutableString学习笔记常用方法

NSString篇:

1.字符串连接

1         NSString *beijing = @"北京";
2         NSString *welcome = [beijing stringByAppendingString:@"  欢迎你 "];//字符串连接
3         NSLog(@"%@",welcome);

  //两种效果相同的字符串连接    
  NSString *str22 = [str20 stringByAppendingFormat:@"%@",str21];
  NSString *str23 = [str20 stringByAppendingString:str21];

2.字符串长度

1 NSLog(@"%zi",welcome.length);//字符串的长度

3.字符串比较

注意比较的是内容，此处并未比较地址

1         BOOL flag = [beijing isEqualToString:@"北京"];//字符串比较
2         NSLog(@"%d",flag);//布尔类型  1相等  0不相等

比较(地址+内容)

1         NSString *sstring1 = [[NSString alloc] initWithFormat:@"123"];
2         NSString *sstring2 = [[NSString alloc] initWithFormat:@"123"];
3         if(sstring1 != sstring2)
4             NSLog(@"地址不相等");
5         else NSLog(@"地址相等");

NSLog(@"%p,%p"sstring1,sstring2);

4.字符串向数据的转换

1         NSString *number = @"123456",*floatNumber = @"1233.45";
2         float aa = [floatNumber floatValue];// 字符串转换成浮点型
3         int  a = [number intValue];//字符串转换成整型
4         NSLog(@"%d,%f",a,aa);

5.字符串本身元素的索引

 1         NSString *seachStr = @"12345.doc";
 2         BOOL f =  [seachStr hasPrefix:@"123"];//判断A字符串是否以B字符串为开头
 3         BOOL f1 = [seachStr hasSuffix:@".doc"];//判断A字符串是否以B字符串结尾
 4         NSRange range = [seachStr rangeOfString:@"234"];//搜索B字符串在A字符串中的范围
 5  //库中的NSRange(包含了位置和长度的结构体)
 6 //        typedef struct _NSRange {
 7 //        NSUInteger location;
 8 //        NSUInteger length;
 9 //        } NSRange;
10         NSLog(@"%d,%d,%lu,%lu",f,f1,(range.location),(range.length));//位置  长度  (unsigned long)
11         
12         if (range.location == NSNotFound)
13         {
14             NSLog(@"没找到");
15         }

6.字符串的裁剪

 1         NSString *subResource = @"abcde";
 2         NSString *subStr = [subResource substringFromIndex:3];//从位置1开始剪切字符串，包含1
 3         NSLog(@"%@",subStr);
 4         
 5         NSString *subStr2 = [subResource substringToIndex:3];//剪切到位置3，不包含3，留下3
 6         NSLog(@"%@",subStr2);
 7 
 8         NSString *subResource = @"abcde";
 9         NSRange range1 = NSMakeRange(1, 2);
10 //        range1.location = 1;//位置
11 //        range1.length = 2;//长度
12 //等价
13 //库中的NSMakeRange
14 //        NS_INLINE NSRange NSMakeRange(NSUInteger loc, NSUInteger len) {
15 //            NSRange r;
16 //            r.location = loc;
17 //            r.length = len;
18 //            return r;
19 //        }
20         NSString *subStr3 = [subResource substringWithRange:range1];//剪切给定范围的字符串
21         //compare方法：1.升序：前 < 后（-1），2.相等0  3.降序：前 > 后（1）
22         NSLog(@"%@",subStr3);

7.字符串的比较

1        NSLog(@"%d",(NSComparisonResult result = [@"ABC" compare:@"abc"]));
2        NSComparisonResult/*枚举类型*/ result = [@"CBA" compare:@"abc" ] ;

3        NSLog(@"%ld",result);// NSOrderedAscending = -1L,存储类型L
4 /*typedef NS_ENUM(NSInteger, NSComparisonResult) {NSOrderedAscending = -1L, NSOrderedSame, NSOrderedDescending};*/

// NSComparisonResult result = [@“” caseInsensitiveCompare:@“”];
不区分大小写的比较

8.字符串元素插入、剔除、替换

1         NSString *string = @"Hello World and Sunshine";
2         NSString *string1= [string stringByReplacingOccurrencesOfS tring:@"World" withString:@"iBokanWisdom"];
3         NSLog(@"替换之前%@替换之后%@",string,string1);

 1 #import <Foundation/Foundation.h>
 2 
 3 int main(int argc, const char * argv[])
 4 {
 5     @autoreleasepool
 6     {
 7         NSString *string = @"Hello World and Sunshine";
 8         NSString *string1= [string stringByReplacingOccurrencesOfString:@"World" withString:@"iBokanWisdom"];
 9         NSLog(@"替换之前%@替换之后%@",string,string1);
10         
11         NSRange range = [string rangeOfString:@"World"];//搜索World字符串在Hello World and Sunshine字符串中的范围
12         NSString *string3 = [string stringByReplacingCharactersInRange:range withString:@"iBokanWisdom"];//某范围插入字符串
13         NSLog(@"%@",string3);
14         NSArray *array = [string componentsSeparatedByString:@" " ];//字符串转换为数组
15         //array = @[@"Hello",@"World",@"and",@"Sunshine"];
16         NSMutableArray *mutableArray = [array mutableCopy];//数组转换
17         [mutableArray replaceObjectAtIndex:1 withObject:@"iBokanWisdom"];//iBokanWisdom替换World
18 //        [NSMutableArray componentsJoinedByString:@" “];
19         NSString *string2 = [mutableArray componentsJoinedByString:@" "];//数组转换为字符串
20         NSLog(@"%@",string2);
21        
22     }
23     return 0;
24 }

// NSString构造方法:

//构造方法，语法跟NSNumber,NSArray差不多
stringWithString:
stringWithFormat:@""

//比较

isEqualTo..

compare

//获取X之前

sub..ToIndex

//截取X到尾

sub..FromIndex

//查找

rangeOf..

NSMutableString篇(注意:可变字符串与不可变字符串的相同操作方法是不同的)

1         NSMutableString *mutableString = [[NSMutableString alloc] initWithCapacity/*容量*/:0];//可变字符串初始化
2         //首先分配0个存储空间，当字符串长度超出范围后，再去开辟新的存储空间
3         [mutableString setString:@"123456"];
4         NSString *sstring;//不可变字符串初始化
5         sstring = @"123456";//不可变字符串赋值
6         [mutableString appendString:@"789"];//可变字符串的追加方法，不产生新的字符串，直接改变原有的字符串
7         NSString *welcome = [sstring stringByAppendingString:@"  欢迎你 "];//不可变字符串的追加方法，要产生新的字符串
8         NSLog(@"%@--%@",mutableString,welcome);
9         //总结:可变字符串只有初始化并且说明长度后才可以对其操作，否则为空

//插入字符串

insertString

//追加字符串

appendString

//替换字符串

deleteCharactersInRange:withString

OC之NSString、NSMutableString学习笔记 常用方法

OC之NSString、NSMutableString学习笔记常用方法