学习ios之二--NSString--NSNumber

//------------------- NSNumber
//创建一个NSNumber
NSNumber * monthNumber=[NSNumber numberWithInt:10];
NSNumber * lengthNumber=[[NSNumber alloc]initWithFloat:10.8];
NSLog(@"monthNumber:%@",monthNumber);
NSLog(@"lengthNumber:%@",lengthNumber);

//还原成基本类型
int month=[monthNumber intValue];
float length=[lengthNumber floatValue];
NSLog(@"month:%d",month);
NSLog(@"length:%1f",length);

//------------------- NSString

//创建空字符串
NSString * string1=@"这是一个字符串常量";
NSString * string2=[[NSString alloc]init];
NSString * string3=[NSString string];

NSLog(@"string1 %@",string1);

NSLog(@"string2 %@",string2);

NSLog(@"string3 %@",string3);

//常量区
NSString * string4=[[NSString alloc]initWithString:@"abc"];
NSString * string5=[NSString stringWithString:string4];

NSLog(@"string4 %@",string4);
NSLog(@"string5 %@",string5);

//堆区
NSString * string6=[[NSString alloc]initWithFormat:@"%d",10];
NSString *string7=[NSString stringWithFormat:@"%f",10.8];

NSLog(@"string6 %@",string6);
NSLog(@"string7 %@",string7);

//内容是否相同
if ([string4 isEqualToString:string5]) {
NSLog(@"same");
}
else{
NSLog(@"different");
}

//同一个对象
if (string1==string2) {
NSLog(@"y");
}

//比较字符串大小
//NSOrderedAscending = -1L, NSOrderedSame, NSOrderedDescending
NSLog(@"%ld",[string4 caseInsensitiveCompare:string5]);

//字符串长度
NSLog(@"%ld",[string4 length]);

//改变字符串大小写
NSString *hello=@"hello WORLD";
NSLog(@"%@",[hello uppercaseString]);//全部大写
NSLog(@"%@",[hello lowercaseString]);// 小写
NSLog(@"%@",[hello capitalizedString]);//首字母大写

//字符串转--基本数据类型
NSString * string11=@"3.3333";
NSLog(@"%d",[string11 boolValue]);
NSLog(@"%f",[string11 floatValue]);
NSLog(@"%f",[string11 doubleValue]);
NSLog(@"%d",[string11 intValue]);

//字符串转数组
NSString * string12=@"abc ddd eee";
NSArray *array=[string12 componentsSeparatedByString:@" "];
NSLog(@"%@",array);

//截取字符串
NSString *string13=[NSString stringWithFormat:@"abcdef"];
//从字符串的开头一直截取到指定位置，但不包括该位置的字符
NSString * string14=[string13 substringToIndex:2];//ab
NSLog(@"string14 %@",string14);
//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串
NSString * string15=[string13 substringFromIndex:2];
NSLog(@"string15 %@",string15);//cedf
//根据范围截取字符串
NSRange range={4,2};
// range.location=4;
// range.length=2;
NSString *string16=[string13 substringWithRange:range];
NSLog(@"string16 %@",string16);//ef

//拼接字符串
NSString * string17=@"1",*string18=@"2";
NSString *string19=[[NSString alloc]initWithFormat:@"拼接：%@ and %@",string17,string18];
NSLog(@"string19 %@",string19);
NSString* string20=[string17 stringByAppendingFormat:@"%@",string18];
NSString *string21=[string17 stringByAppendingString:string18];
NSLog(@"string20 %@",string20);
NSLog(@"string21 %@",string21);

//查询字符串
NSString *sting22=@"skjdlfjskldfaaaajsldjfklsjdfsjkajdkf";
NSRange range11=[sting22 rangeOfString:@"aaaa"];
if (range11.location!=NSNotFound) {
NSLog(@"找到");
}

//可变字符串 继承NSString
//插入
NSMutableString *str=[NSMutableString stringWithString:@"skjlfjksljdkf"];
[str insertString:@"11111" atIndex:0];
NSLog(@"%@",str);
//删除
[str deleteCharactersInRange:NSMakeRange(1,2)];
NSLog(@"%@",str);

//替换
[str replaceCharactersInRange:NSMakeRange(0, 2) withString:@"45"];
NSLog(@"%@",str);