字符串汇总

1.截取字符串

NSString*string =@"sdfsfsfsAdfsdf";
string = [string substringToIndex:7];//截取掉下标7之前的字符串
NSLog(@"截取的值为：%@",string);
[string substringFromIndex:2];//截取掉下标2之后的字符串
NSLog(@"截取的值为：%@",string);

2.匹配字符串
NSString*string =@"sdfsfsfsAdfsdf";
NSRangerange = [stringrangeOfString:@"f"];//匹配得到的下标
NSLog(@"rang:%@",NSStringFromRange(range));
string = [string substringWithRange:range];//截取范围类的字符串
NSLog(@"截取的值为：%@",string);

3.分隔字符串
NSString*string =@"sdfsfsfsAdfsdf";
NSArray *array = [string componentsSeparatedByString:@"A"]; //从字符A中分隔成2个元素的数组
NSLog(@"array:%@",array); //结果是adfsfsfs和dfsdf

4.将NSData转化为NSString
NSString* str = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];

5.将NSString 转化为NSData
- (NSData *)dataUsingEncoding:(NSStringEncoding)encoding;

6.在以上方法中，提升速度:initWithString方法
NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];
7.用标准c创建字符串:initWithCString方法

char *Cstring = "This is a String!";
   NSString *astring = [[NSString alloc] initWithCString:Cstring];
8.创建格式化字符串:占位符（由一个%加一个字符组成）
int i = 1;
   int j = 2;
   NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"%d.This is %i string!",i,j]];

9.创建临时字符串
NSString *astring;
astring = [NSString stringWithCString:"This is a temporary string"];
NSLog(@"astring:%@",astring);

//1、创建常量字符串。
NSString *astring = @"This is a String!";

//2、创建空字符串，给予赋值。
NSString *astring = [[NSString alloc] init];
astring = @"This is a String!";
[astring release];
NSLog(@"astring:%@",astring);

//3、在以上方法中，提升速度:initWithString方法
NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];
NSLog(@"astring:%@",astring);
[astring release];

//4、用标准c创建字符串:initWithCString方法
char *Cstring = "This is a String!";
NSString *astring = [[NSString alloc] initWithCString:Cstring];
NSLog(@"astring:%@",astring);
[astring release];

//5、创建格式化字符串:占位符（由一个%加一个字符组成）
int i = 1;
int j = 2;
NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"%d.This is %i string!",i,j]];
NSLog(@"astring:%@",astring);
[astring release];

//6、创建临时字符串
NSString *astring;
astring = [NSString stringWithCString:"This is a temporary string"];
NSLog(@"astring:%@",astring);

/*----------------从文件读取字符串:initWithContentsOfFile方法----------------*/
NSString *path = @"astring.text";
NSString *astring = [[NSString alloc] initWithContentsOfFile:path];
NSLog(@"astring:%@",astring);
[astring release];

/*----------------写字符串到文件:writeToFile方法----------------*/

NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];
NSLog(@"astring:%@",astring);
NSString *path = @"astring.text";
[astring writeToFile: path atomically: YES];
[astring release];

/*----------------比较两个字符串----------------*/

//用C比较:strcmp函数
char string1[] = "string!";
char string2[] = "string!";
if(strcmp(string1, string2) = = 0)
{
NSLog(@"1");
}

//isEqualToString方法
NSString *astring01 = @"This is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 isEqualToString:astring02];
NSLog(@"result:%d",result);

//compare方法(comparer返回的三种值)
NSString *astring01 = @"This is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 compare:astring02] = = NSOrderedSame;
NSLog(@"result:%d",result);
//NSOrderedSame判断两者内容是否相同

NSString *astring01 = @"This is a String!";
NSString *astring02 = @"this is a String!";
BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;
NSLog(@"result:%d",result);
//NSOrderedAscending判断两对象值的大小(按字母顺序进行比较，astring02大于astring01为真)

NSString *astring01 = @"this is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 compare:astring02] = = NSOrderedDescending;
NSLog(@"result:%d",result);
//NSOrderedDescending判断两对象值的大小(按字母顺序进行比较，astring02小于astring01为真)

//不考虑大小写比较字符串1
NSString *astring01 = @"this is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 caseInsensitiveCompare:astring02] = = NSOrderedSame;
NSLog(@"result:%d",result);
//NSOrderedDescending判断两对象值的大小(按字母顺序进行比较，astring02小于astring01为真)

//不考虑大小写比较字符串2
NSString *astring01 = @"this is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 compare:astring02
options:NSCaseInsensitiveSearch | NSNumericSearch] = = NSOrderedSame;
NSLog(@"result:%d",result);

//NSCaseInsensitiveSearch:不区分大小写比较 NSLiteralSearch:进行完全比较，区分大小写 NSNumericSearch:比较字符串的字符个数，而不是字符值。

/*----------------改变字符串的大小写----------------*/
NSString *string1 = @"A String";
NSString *string2 = @"String";
NSLog(@"string1:%@",[string1 uppercaseString]);//大写
NSLog(@"string2:%@",[string2 lowercaseString]);//小写
NSLog(@"string2:%@",[string2 capitalizedString]);//首字母大小

/*---------------在串中搜索子串----------------*/
NSString *string1 = @"This is a string";
NSString *string2 = @"string";
NSRange range = [string1 rangeOfString:string2];
int location = range.location;
int leight = range.length;
NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"Location:%i,Leight:%i",location,leight]];
NSLog(@"astring:%@",astring);
[astring release];

/*----------------抽取子串 ----------------*/

//-substringToIndex: 从字符串的开头一直截取到指定的位置，但不包括该位置的字符
NSString *string1 = @"This is a string";
NSString *string2 = [string1 substringToIndex:3];
NSLog(@"string2:%@",string2);

//-substringFromIndex: 以指定位置开始（包括指定位置的字符），并包括之后的全部字符
NSString *string1 = @"This is a string";
NSString *string2 = [string1 substringFromIndex:3];
NSLog(@"string2:%@",string2);

//-substringWithRange: //按照所给出的位置，长度，任意地从字符串中截取子串
NSString *string1 = @"This is a string";
NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];
NSLog(@"string2:%@",string2);

//扩展路径
NSString *Path = @"~/NSData.txt";
NSString *absolutePath = [Path stringByExpandingTildeInPath];
NSLog(@"absolutePath:%@",absolutePath);
NSLog(@"Path:%@",[absolutePath stringByAbbreviatingWithTildeInPath]);

//文件扩展名
NSString *Path = @"~/NSData.txt";
NSLog(@"Extension:%@",[Path pathExtension]);

/*******************************************************************************************
NSMutableString
*******************************************************************************************/

/*---------------给字符串分配容量----------------*/
//stringWithCapacity:
NSMutableString *String;
String = [NSMutableString stringWithCapacity:40];

/*---------------在已有字符串后面添加字符----------------*/

//appendString: and appendFormat:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
//[String1 appendString:@", I will be adding some character"];
[String1 appendFormat:[NSString stringWithFormat:@", I will be adding some character"]];
NSLog(@"String1:%@",String1);
*/

/*--------在已有字符串中按照所给出范围和长度删除字符------*/
/*
//deleteCharactersInRange:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 deleteCharactersInRange:NSMakeRange(0, 5)];
NSLog(@"String1:%@",String1);

/*--------在已有字符串后面在所指定的位置中插入给出的字符串------*/

//-insertString: atIndex:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 insertString:@"Hi! " atIndex:0];
NSLog(@"String1:%@",String1);

/*--------将已有的空符串换成其它的字符串------*/

//-setString:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 setString:@"Hello Word!"];
NSLog(@"String1:%@",String1);

/*--------按照所给出的范围，和字符串替换的原有的字符------*/

//-setString:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 replaceCharactersInRange:NSMakeRange(0, 4) withString:@"That"];
NSLog(@"String1:%@",String1);

/*-------------判断字符串内是否还包含别的字符串(前缀，后缀)-------------*/
//01：检查字符串是否以另一个字符串开头- (BOOL) hasPrefix: (NSString *) aString;
NSString *String1 = @"NSStringInformation.txt";
[String1 hasPrefix:@"NSString"] = = 1 ?NSLog(@"YES") : NSLog(@"NO");
[String1 hasSuffix:@".txt"] = = 1 ?NSLog(@"YES") : NSLog(@"NO");

//02：查找字符串某处是否包含其它字符串 - (NSRange) rangeOfString: (NSString *) aString，这一点前面在串中搜索子串用到过;

iOS字符串常用处理方法

1.根据起始位置和长度进行字符串截取－ substringWithRange
方法说明：
- (NSString *)substringWithRange:(NSRange)aRange
其中关于 NSRange 的生成方式：
NSRange NSMakeRange (
   NSUInteger loc,
   NSUInteger len
);
其中 loc表示左边开始的位置（第1位为0，从0开始计算），len表示要截取的长度。
例子：
NSString* value = [@"2015-09-30~20:30:34" substringWithRange:NSMakeRange(11,5)];
说明：NSMakeRange(11,5)表示字符串从左开始经过11个字符，然后从第12个字符开始取5个字符。
value的值为20:30

2.字符串截取到第n位－ substringToIndex
方法说明：
- (NSString *)substringToIndex:(NSUInteger)anIndex
例子：
NSString* value = [@"2015-09-30~20:30:34" substringToIndex:10];
value的值为2015-09-30

3.从n位进行字符串截取
－ substringFromIndex
方法说明：
- (NSString *)substringFromIndex:(NSUInteger)anIndex
例子：
NSString* value = [@"2015-09-30~20:30:34" substringFromIndex:10];
value的值为~20:30:34

4.将字符串分割为数组
－componentsSeparatedByString
方法说明：
- (NSArray<NSString *> * _Nonnull)componentsSeparatedByString:(NSString * _Nonnull)separator
例子：
使用-componentsSeparatedByString:来切分字符串为NSArray。如：
引用
NSString *string = @”one:two:three”;
NSArray *aArray = [string componentsSeparatedByString:@":"];
那么aArray就是one two three三个字符串的数组。

5.将数组连接为字符串
－componentsJoinedByString
方法说明：
- (NSString * _Nonnull)componentsJoinedByString:(NSString * _Nonnull)separator
例子：
NSArray* arr = [NSArray arrayWithObjects:@"A",@"B",@"C", nil];
    NSString* str = [arr componentsJoinedByString:@","];
这样，arr数组中的各个元素就以”,”分割形成一个字符串 A,B,C。

6.将数组连接为字符串
－UTF8String
方法说明：
@property (nullable, readonly) __strong const char *UTF8String NS_RETURNS_INNER_POINTER;
// Convenience to return null-terminated UTF8 representation
例子：
const char* str = [@"中文china" UTF8String];

7.将字符串转为unsigned long格式
strtoul
方法说明：
unsigned long strtoul(const char *nptr,char **endptr,int base )
参数1：字符串起始地址
参数2：返回字符串有效数字的结束地址，这也是为什么要用二级指针的原因。
参数3：进制转换基数。如果base=0，自动对字符串里的数字格式进行分析，并返回基数，其值可取8、16、10。当base=0,自动判断字符串的类型，并按10进制输出，例如"0xa",就会把字符串当做16进制处理，输出的为10。
例子：
const char* str = [@"0xFF" UTF8String];
unsigned long value = strtoul(str, NULL, 0);
此时value值为255

关于c中的进制说明：

16进制以0x开头，后面跟数字0~9或字母A~F（小写也可以）。如：0xFF（16进制数FF，转为10进制就是255）
8进制以0开头，后面跟数字0~7。如：011（8进制数11,转为10进制就是9）

//创建一个字符串常量
NSString *string100=@"这是一个常量，";
//创建一个空字符串
NSString *string101=[[NSString alloc] init];
NSString *string102=[NSString string];
//快速创建字符串
NSString *string103=[[NSString alloc] initWithString:@"abc"];
NSString *string104=[NSString stringWithString:@"def"];
  
//创建一个格式化的字符
NSString *string105=[[NSString alloc] initWithFormat:@"%d" ,10];
NSString *string106=[NSString stringWithFormat:@"%f",11.5];
  
//字符串转换
NSString *string107=@"abc";
NSString *string108=@"ABC";
NSLog(@"uppercase:%@",[string107 uppercaseString]);//打印出ABC
NSLog(@"lowercase:%@",[string108 lowercaseString]);//打印出abc
NSLog(@"capitalized:%@",[string107 capitalizedString]);//大写首字母
  
//字符比较
NSString *string109=@"abc";
NSString *string111=[[NSString alloc] initWithFormat:@"abc"];
if ([string109 isEqualToString:string111]) {
    NSLog(@"相同内容");
}else{
    NSLog(@"内容不同");
}
if (string109 == string111) {//等号是指针
    NSLog(@"内存指针相同");
}else{
    NSLog(@"内存指针不同");
}
  
//求字符串长度
NSString * string112=[[NSString alloc] initWithFormat:@"abcd"];
NSLog(@"字符串长度：%hd",[string112 length]);
  
  
//拼接字符串
NSString *string10=@"abc";
NSString *string11=@"def";
NSLog(@"string10+string11:%@",[string10 stringByAppendingFormat:@"%@",string11]);
NSLog(@"string0+string11:%@",[string10 stringByAppendingString:string11]);
NSLog(@"string10+string11:%@",[[NSString alloc] initWithFormat: @"%@%@",string10,string11]);
  
//截取字符串
NSString *string=[[NSString alloc] initWithString:@"abcdefg"];
NSString *substring1=[string substringToIndex:2];
NSString *substring2=[string substringFromIndex:2];
NSRange range={2,4};
NSLog(@"rang:%@",[string substringWithRange:range]);
NSLog(@"1:%@",substring1);
NSLog(@"2:%@",substring2);
  
//查找字符串
NSString *searchstring=[[NSString alloc] initWithString:@"abcabcuu"];
NSRange aa=[searchstring rangeOfString:@"uu"];
if (aa.location != NSNotFound) {
   NSLog(@"searchstring:%@",@"aa");
}
  
//可变字符串 NSMutableString
NSMutableString *string200=[[NSMutableString alloc] initWithFormat:@"abc" ];
//插入
[string200 insertString:@"insert" atIndex:0 ];
NSLog(@"insertstring:%@",string200);
//替换
[string200 replaceCharactersInRange:NSMakeRange(1, 2) withString:@"ddddddd"];
NSLog(@"insertstring:%@",string200);
//删除
[string200 deleteCharactersInRange:NSMakeRange(1, 2) ];
NSLog(@"insertstring:%@",string200);

posted on 2016-09-29 16:47 墨鱼哥哥阅读(80) 评论(0) 收藏举报

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