1、创建常量字符串
NSString *astring = @"This is a String!";
2、创建空字符串，再给予赋值
NSString *astring = [[NSString alloc] init];
astring = @"This is a String!";
[astring release];
NSLog(@"astring:%@",astring);
NSString *astring = [[NSString alloc] init];
NSLog(@"0x%.8x", astring);
astring=@"This is a String!";
NSLog(@"0x%.8x", astring);
[astring release];
NSLog(@"astring:%@",astring);
3、用initWithString方法提升速度:
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);
7、从文件创建字符串
NSString *path = [[NSBundlemainBundle] pathForResource:@"astring.text"ofType:nil];
NSString *astring = [[NSString alloc] initWithContentsOfFile:path];
NSLog(@"astring:%@",astring);
[astring release];
8、用字符串创建字符串，并写入到文件
NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];
NSLog(@"astring:%@",astring);
NSString *path = @"astring.text";
[astring writeToFile: path atomically: YES];
[astring release];
注：此路径path只只是示意，真实路径并非如此
9、用C比较:strcmp函数
char string1[] = "string!";
char string2[] = "string!";
if(strcmp(string1, string2) == 0)
{
NSLog(@"1");
}
10、isEqualToString方法
复制代码
NSString *astring01 = @"This is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 isEqualToString:astring02];
NSLog(@"result:%d",result);
11、考虑大小写比较2个字符串
void compareString() {
NSComparisonResult result = [@"bmn" compare:@"azz"];
if (result == NSOrderedSame) {
NSLog(@"左 ＝＝ 右");
}else if (result == NSOrderedDescending) {
NSLog(@"左 > 右");
}else if (result == NSOrderedAscending) {
NSLog(@"左 <</span> 右");
}
}
12、不考虑大小写比较字符串
void compareString() {
NSComparisonResult caseInsenresult = [@"dffA" caseInsensitiveCompare:@"dffa"];
if (caseInsenresult == NSOrderedSame) {
NSLog(@"左 ＝＝ 右");
}else if (caseInsenresult == NSOrderedDescending) {
NSLog(@"左 > 右");
}else if (caseInsenresult == NSOrderedAscending) {
NSLog(@"左 <</span> 右");
}
}
13、输出大写或者小写字符串
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
14、rangeOfString查找字符串中是否包含其它字符串
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);
if (range.location == NSNotFound) {
NSLog(@"str中没有找到 567");
}else {
NSLog(@"搜索范围 %@",NSStringFromRange(range));
}
// 或者
// if (range.length == 0 ) {
// NSLog(@"str中没有找到 567");
// }
[astring release];
15、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);
16、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);
17、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);
18、stringWithCapacity: 按照固定长度生成空字符串
NSMutableString *String;
String = [NSMutableString stringWithCapacity:40];
19、-appendString与-appendFormatm 把一个字符串接在另一个字符串的末尾
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);
20、insertString: atIndex 在指定位置插入字符串
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 insertString:@"Hi! " atIndex:0];
NSLog(@"String1:%@",String1);
21、-setString:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 setString:@"Hello Word!"];
NSLog(@"String1:%@",String1);
22、replaceCharactersInRange: withString 用指定字符串替换字符串中某指定位置、长度的字符串
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 replaceCharactersInRange:NSMakeRange(0, 4) withString:@"That"];
NSLog(@"String1:%@",String1);
23、hasPrefix 检查字符串是否以另一个字符串开头
NSString *String1 = @"NSStringInformation.txt";
[String1 hasPrefix:@"NSString"] = = 1 ? NSLog(@"YES") : NSLog(@"NO");
[String1 hasSuffix:@".txt"] = = 1 ? NSLog(@"YES") : NSLog(@"NO");
24、扩展路径
NSString *Path = @"~/NSData.txt";
NSString *absolutePath = [Path stringByExpandingTildeInPath];
NSLog(@"absolutePath:%@",absolutePath);
NSLog(@"Path:%@",[absolutePath stringByAbbreviatingWithTildeInPath]);
25、取文件扩展名
NSString *Path = @"~/NSData.txt";
NSLog(@"Extension:%@",[Path pathExtension]);