iOS NSString的常用用法

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溫故知新，常用常新 //1、建立常量字串。

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

 //2、建立Null 字元串，給予賦值。

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

//

NSString *astring = [[NSString alloc] init];
 
NSLog(@"0x%.8x", astring);
 
[email protected]"This is a String!";
 
NSLog(@"0x%.8x", astring);
 
[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、用標準c建立字串:initWithCString方法

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

 //5、建立格式化字串:預留位置（由一個%加一個字元組成）

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、建立臨時字串

NSString *astring;
 
astring = [NSString stringWithCString:"This is a temporary string"];
 
NSLog(@"astring:%@",astring);

 

//7、從檔案建立字串

NSString *path = [[NSBundlemainBundle] pathForResource:@"astring.text"ofType:nil];

NSString *astring = [[NSString alloc] initWithContentsOfFile:path];

NSLog(@"astring:%@",astring);

[astring release];

 

//8、用字串建立字串，並寫入到檔案

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

註：此路徑path只只是示意，真實路徑並非如此 //9、用C比較:strcmp函數

char string1[] = "string!";
 
char string2[] = "string!";
 
if(strcmp(string1, string2) == 0)
{
 
    NSLog(@"1");
 
}

 

//10、isEqualToString方法

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

 

//11、compare方法(comparer返回的三種值)

//
NSString *astring01 = @"This is a String!";
 
NSString *astring02 = @"This is a String!";    
 
BOOL result = [astring01 compare:astring02] == NSOrderedSame;    //NSOrderedSame判斷兩者內容是否相同
 
NSLog(@"result:%d",result);    
 
//
NSString *astring01 = @"This is a String!";
 
NSString *astring02 = @"this is a String!";
 
BOOL result = [astring01 compare:astring02] == NSOrderedAscending;    //NSOrderedAscending判斷兩對象值的大小(按字母順序進行比較，astring02大於astring01為真)
 
NSLog(@"result:%d",result);

//
NSString *astring01 = @"this is a String!";
 
NSString *astring02 = @"This is a String!";
 
BOOL result = [astring01 compare:astring02] == NSOrderedDescending;    //NSOrderedDescending判斷兩對象值的大小(按字母順序進行比較，astring02小於astring01為真)
 
NSLog(@"result:%d",result);     
 

 

//12、不考慮大小寫比較字串

//1.
NSString *astring01 = @"this is a String!";
 
NSString *astring02 = @"This is a String!";
 
BOOL result = [astring01 caseInsensitiveCompare:astring02] == NSOrderedSame;    //NSOrderedDescending判斷兩對象值的大小(按字母順序進行比較，astring02小於astring01為真)

NSLog(@"result:%d",result); 

//2.
NSString *astring01 = @"this is a String!";
 
NSString *astring02 = @"This is a String!";
 
BOOL result = [astring01 compare:astring02
 
options:NSCaseInsensitiveSearch | NSNumericSearch] == NSOrderedSame;    //NSCaseInsensitiveSearch:不區分大小寫比較 NSLiteralSearch:進行完全比較，區分大小寫 NSNumericSearch:比較字串的字元個數，而不是字元值。
 
NSLog(@"result:%d",result); 

 //13、輸出大寫或者小寫字串

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

 

//14、-rangeOfString: //尋找字串某處是否包含其它字串

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];

 

//15、-substringToIndex: 從字串的開頭一直截取到指定的位置，但不包括該位置的字元

NSString *string1 = @"This is a string";
 
NSString *string2 = [string1 substringToIndex:3];
 
NSLog(@"string2:%@",string2);

 

//16、-substringFromIndex: 以指定位置開始（包括指定位置的字元），並包括之後的全部字元

NSString *string1 = @"This is a string";
 
NSString *string2 = [string1 substringFromIndex:3];
 
NSLog(@"string2:%@",string2);

 

//17、-substringWithRange: //按照所給出的位置，長度，任意地從字串中截取子串

NSString *string1 = @"This is a string";
 
NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];
 
NSLog(@"string2:%@",string2);

 

//18、-stringWithCapacity: //按照固定長度產生Null 字元串

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

 //19、-appendString: and -appendFormat: //把一個字串接在另一個字串的末尾

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: //用指定字串替換字串中某指定位置、長度的字串

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

 //23、-hasPrefix: //檢查字串是否以另一個字串開頭

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

 //24、擴充路徑

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

 

//25、副檔名

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

iOS NSString的常用用法