OC语言中字符串的使用

可变字符串

//插入字符串

NSMutableString*string1=[NSMutableStringstringWithString:@"字符串"];[string1insertString:@"可变"atIndex:0];//在string的第0个位置插入NSLog(@"string=%@",string1);//可变字符串

//删除字符串

NSMutableString*string2=[NSMutableStringstringWithString:@"aabb字符串"];NSRangerange=NSMakeRange(0,4);//指定范围第一个位置，长度为4[string2deleteCharactersInRange:range];//删除指定范围的字符串NSLog(@"string2=%@",string2);//字符串

//追加字符串

NSMutableString*string3=[NSMutableStringstringWithString:@"字符串"];[string3appendString:@"追加"];NSLog(@"string3=%@",string3);//追加字符串

字符串

//比较字符串内容是否相同

NSString*s1=[NSStringstringWithFormat:@"字符串"];NSString*s2=[NSStringstringWithFormat:@"字符串"];//比较的是指针地址if(s1==s2){NSLog(@"s1==s2");}elseNSLog(@"s1!=s2");//s1!=s2//比较字符串的内容boolisSame=[s1isEqualToString:s2];if(isSame){NSLog(@"s1==s2");}elseNSLog(@"s1!=s2");//s1==s2

//比较字符串大小

NSString*n1=[NSStringstringWithFormat:@"a"];NSString*n2=[NSStringstringWithFormat:@"b"];NSComparisonResultresult=[n1caseInsensitiveCompare:n2];if(result==NSOrderedAscending){NSLog(@"升序：a<b");}elseif(result==NSOrderedSame){NSLog(@"内容相同");}elseif(result==NSOrderedDescending){NSLog(@"降序:a>b");}//a<b

//访问字符串长度

NSString*nns=@"HWELWE";NSUIntegerlen=[nnslength];NSLog(@"lenis%ld",len);//6

//大小写转换

NSString*hello=@"helloWORLD";NSLog(@"%@",[hellouppercaseString]);//全部大写//HELLOWORLDNSLog(@"%@",[hellolowercaseString]);//全部小写//helloworldNSLog(@"%@",[hellocapitalizedString]);//首字母大写，其他字母小写//HelloWorld

//转换为基本数据类型

NSString*st1=@"10";inta=[st1intValue];NSLog(@"a=%d",a);//10NSString*st2=@"10.23";floatb=[st2floatValue];NSLog(@"b=%.2f",b);//10.23NSString*st3=@"1";BOOLc=[st3boolValue];NSLog(@"c=%d",c);//1

//分割字符串

NSString*str=@"asfs-dfgf-sgfds,fdsa";NSArray*arr=[strcomponentsSeparatedByString:@"-"];NSLog(@"%@",arr);//访问指定位置字符NSString*string=@"abcdefg";chars=[stringcharacterAtIndex:3];NSLog(@"s=%c",s);//d

//截取字符串

NSString*ss=@"abcdef";//截取到指定位置NSString*string1=[sssubstringToIndex:3];NSLog(@"string1=%@",string1);//abc//从指定位置截取到末尾NSString*string2=[sssubstringFromIndex:2];NSLog(@"string2=%@",string2);//指定范围截取NSRangerange=NSMakeRange(2,3);//从下标2开始截取3位NSString*string3=[sssubstringWithRange:range];NSLog(@"string3=%@",string3);

//拼接字符串

NSString*ns1=@"abx";NSString*ns2=@"ycd";NSString*strr1=[NSStringstringWithFormat:@"字符串1:%@,字符串2：%@",ns1,ns2];//字符串1:abx,字符串2：ycdNSLog(@"strr=%@",strr1);NSString*strr2=[ns1stringByAppendingString:ns2];NSLog(@"strr2=%@",strr2);//abxycdNSString*strr3=[ns1stringByAppendingFormat:@"追加字符串2：%@",ns2];NSLog(@"strr3=%@",strr3);//abx追加字符串2：ycd

//查找字符串

NSString*email=@"123456@qq.com";NSString*substring=@"@qq.com";NSRangerange1=[emailrangeOfString:substring];if(range1.location!=NSNotFound){NSLog(@"%@包含%@",email,substring);NSLog(@"位置是：%ld,长度是%ld",range1.location,range1.length);}else{NSLog(@"没找到");}//位置是：6,长度是7

//替换字符串

NSString*newemail=[emailstringByReplacingOccurrencesOfString:@"qq.com"withString:@"163.com"];NSLog(@"newemail=%@",newemail);//newemail=123456@163.com