Objective-C基础：字符串

NSString *astring = @"This is a String!";

NSString *astring = [[NSString alloc] init];
astring = @"This is a String!";
NSLog(@"astring:%@",astring);

char *Cstring = "This is a String!";
NSString *astring = [[NSString alloc] initWithCString:Cstring];
NSLog(@"astring:%@",astring);

int i = 1;
int j = 2;
NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"%d.This is %i string!",i,j]];
NSLog(@"astring:%@",astring);

NSUInteger uLen1 = [astring length];
NSLog(@"uLen = %lu", uLen1);

NSString *path = @"astring.text";
NSString *astring = [[NSString alloc] initWithContentsOfFile:path];
NSLog(@"astring:%@",astring);

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

//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(相等返回1)
NSString *astring01 = @"This is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 compare:astring02] == NSOrderedSame;
NSLog(@"result:%d",result);

//NSOrderedAscending判断两者内容是否相同(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] == NSOrderedAscending;
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)
NSString *astring01 = @"this is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 compare:astring02] == NSOrderedDescending;
NSLog(@"result:%d",result);

//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);

//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。

NSString *string1 = @"A String";
NSString *string2 = @"string";
NSLog(@"string1:%@",[string2 uppercaseString]);//大写
NSLog(@"string2:%@",[string1 lowercaseString]);//小写
NSLog(@"string2:%@",[string2 capitalizedString]);//首字母大小

NSString *string1 = @"This is a string";
NSString *string2 = @"string";
NSRange range = [string1 rangeOfString:string2];
NSUInteger location = range.location;
NSUInteger length = range.length;
NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"Location:%lu,Length:%lu",(unsigned long)location,	(unsigned long)length]];
NSLog(@"astring:%@",astring);

//结果：astring:Location:11,Length:6

//-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(3, 4)];
NSLog(@"string2:%@",string2);

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

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

NSMutableString *String;
String = [NSMutableString stringWithCapacity:40];

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

//appendFormat:
NSMutableString *String2 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String2 appendFormat:[NSString stringWithFormat:@", I will be adding some character With Format."]];
NSLog(@"String2:%@",String2);

//deleteCharactersInRange:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 deleteCharactersInRange:NSMakeRange(0, 5)];
NSLog(@"String1:%@",String1);

//-insertString: atIndex:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"0123456789"];
[String1 insertString:@"^" atIndex:0];
NSLog(@"String1:%@",String1);

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

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

//- (BOOL) hasPrefix: (NSString *) aString;
NSString *String1 = @"NSStringInformation.txt";
[String1 hasPrefix:@"NSString"] == 1 ?NSLog(@"YES") : NSLog(@"NO");
[String1 hasSuffix:@".txt"] == 1 ?NSLog(@"YES") : NSLog(@"NO");

NSString *String1 = @"NSStringInformation.txt";
NSRange iStart = [String1 rangeOfString:@"String"];
NSLog(@"iStart length is %lu:",(unsigned long)iStart.length);