字符串相关：

30 字符串相关：
30.1追加字符：
NSMutableString *string = [[NSMutableString alloc] init];
string=@“你好”；
[string appendFormat:@"中国"];

30.2字符串替换：把info中所有的<都替换成#
NSString *stroneIntro=[info stringByReplacingOccurrencesOfString:@"<" withString:@"#"];

30.3字符串比较：
Bool IsTrue=[@"Nob"isEqualToString:@"Mob"]

30.4 不考虑大小写比较字符串
NSString *astring01 = @"this is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 caseInsensitiveCompare:astring02] = =NSOrderedSame;

30.5 改变字符串的大小写
NSString *string1 = @"A String"; 
NSString *string2 = @"String"; 
NSLog(@"string1:%@",[string1uppercaseString]);//大写
NSLog(@"string2:%@",[string2lowercaseString]);//小写
NSLog(@"string2:%@",[string2capitalizedString]);//首字母大小

30.6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:[NSStringstringWithFormat:@"Location:%i,Leight:%i",location,leight]];
NSLog(@"astring:%@",astring);
[astring release];

30.7 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 = [string1substringFromIndex: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);

30.8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);

30.9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);

30.10 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);

30.11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);

30.12 -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;