NSString一些常用方法

ios

NSString一些常用方法

从文件创建字符串

1
2
3
4
NSString *path = [[NSBundlemainBundle] pathForResource:@"astring.text"ofType:nil];
NSString *astring = [[NSString alloc] initWithContentsOfFile:path];
NSLog(@"astring:%@",astring);
[astring release];

用字符串创建字符串，并写入到文件

[astring writeToFile: path atomically: YES];

isEqualToString方法

BOOL result = [astring01 isEqualToString:astring02];

compare方法(comparer返回的三种值)

BOOL result = [astring01 compare:astring02] == NSOrderedSame或者NSOrderedAscending或者NSOrderedDescending

不考虑大小写比较字符串

1
2
3
BOOL result = [astring01 caseInsensitiveCompare:astring02] == NSOrderedSame;
BOOL result = [astring01 compare:astring02
options:NSCaseInsensitiveSearch | NSNumericSearch] == NSOrderedSame;    //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。

输出大写或者小写字符串

1
2
3
NSLog(@"string1:%@",[string1 uppercaseString]);//大写
NSLog(@"string2:%@",[string2 lowercaseString]);//小写 
NSLog(@"string2:%@",[string2 capitalizedString]);//首字母大小

查找字符串某处是否包含其它字符串

1
2
3
4
5
NSString *string1 = @"This is a string";
NSString *string2 = @"string";
NSRange range = [string1 rangeOfString:string2];
int location = range.location; 
int leight = range.length;

字符串截取

  • 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 *string2 = [string1 substringToIndex:3];

  • 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 *string2 = [string1 substringFromIndex:3];

  • 按照所给出的位置，长度，任意地从字符串中截取子串

    NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];

按照固定长度生成空字符串

NSMutableString *String = [NSMutableString stringWithCapacity:40];

把一个字符串接在另一个字符串的末尾

1
2
[String1 appendString:@", I will be adding some character"];
[String1 appendFormat:[NSString stringWithFormat:@", I will be adding some character"]];

在指定位置插入字符串

[String1 insertString:@"Hi! " atIndex:0];

setString:

NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 setString:@"Hello Word!"];

用指定字符串替换字符串中某指定位置、长度的字符串

1
2
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 replaceCharactersInRange:NSMakeRange(0, 4) withString:@"That"];

检查字符串是否以另一个字符串开头

1
2
[String1 hasPrefix:@"NSString"] = = 1 ?  NSLog(@"YES") : NSLog(@"NO");
[String1 hasSuffix:@".txt"] = = 1 ?  NSLog(@"YES") : NSLog(@"NO");

扩展路径

NSString *Path = @"~/NSData.txt";
NSString *absolutePath = [Path stringByExpandingTildeInPath];