iOS擷取NSString字串

黑暗森林的歌者發表於2018-02-26
iOS字串

NSString類中提供了這樣三個方法用於獲取子字串：

  • substringFromIndex:
  • substringWithRange:
  • substringToIndex:

具體的使用見下面程式碼即可知道。

NSString *str = @"12345";

 

// NSString *subString0 = [str substringFromIndex:-1];   //會放生越界錯誤

NSString *subString1 = [str substringFromIndex:0];       //@"12345"

NSString *subString2 = [str substringFromIndex:1];       //@"2345"

NSString *subString3 = [str substringFromIndex:4];       //@"5"

NSString *subString4 = [str substringFromIndex:5];       //@""

// NSString *subString5 = [str substringFromIndex:6];   //會放生越界錯誤



// NSString *subString10 = [str substringToIndex:-1];    //會放生越界錯誤

NSString *subString11 = [str substringToIndex:0];         //@"“

NSString *subString12 = [str substringToIndex:1];         //@"1”

NSString *subString13 = [str substringToIndex:4];         //@"1234“

NSString *subString14 = [str substringToIndex:5];         //@"12345”

// NSString *subString15 = [str substringToIndex:6];     //會放生越界錯誤



NSRange range1 = NSMakeRange(-1, 5);

NSRange range2 = NSMakeRange(0, 6);

NSRange range3 = NSMakeRange(0, 5);

NSRange range4 = NSMakeRange(1, 4);

NSRange range5 = NSMakeRange(0, 0);

NSRange range6 = NSMakeRange(4, 1);



//NSString *subString31 = [str substringWithRange:range1]; //會放生越界錯誤

//NSString *subString32 = [str substringWithRange:range2]; //會放生越界錯誤

NSString *subString33 = [str substringWithRange:range3];   //@"12345“

NSString *subString34 = [str substringWithRange:range4];   //@"2345”

NSString *subString35 = [str substringWithRange:range5];   //@"”

NSString *subString36 = [str substringWithRange:range6];   //@"5”
複製程式碼

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