进击的Objective-C -------------------NSSting,NSSMutableString和NSArray,NSMutableArray

NSString 

1.赋值

NSString *s1 = @“123”;

2.初始化方法

NSString *s2 = [[NSString alloc]init];

3. 便利构造器

NSString *s3 = [NSString string];

4.格式化初始化字符串

NSString *s4 = [[NSString alloc]initWithFormat:@“boomshakalaka”];

NSString *s5 = [NSString stringWithFormat:@“lalalala”];

NSString *s6 = [NSString stringWithFormat:@“%@shakalaka”,@“boom”];

NSString *ss = [NSString stringWithFormat:@“%dlalala”,8];

5.通过路径获取字符串

NSString * s7 = [NSString stringWithContentsOfFile:@“路径”encoding:NSUTF8StringEncoding error:nil];

6.字符串长度g        

NSlog(@“%lu“,[s6 length];

7.判断是否有前后缀

NSString *s8 = @“abc123”;

BOOL b1 = [s8 hasPrefix:@“abc”];

BOOL b2 = [s8 hasSuffix:@“3”];

NSLog(@“%d”,b1);

NSLog(@“%d”,b2);

8.大小写转换

小->大

NSString * s9 = [s8 uppercaseString];

NSLog(@“%@“,s9);

大->小

NSString * s10 = [s9 lowercaseString];

NSLog(@“%@“,s10); 

9.比较两个字符串大小

NSComparisonResult r1 = [s8 compare:@“b”];

NSLog(@“%ld”,r1);

10.比较字符串是否相等

BOOL b3 = [s8 isEqualToString:s9];

NSLog(@“%d”,b3);

11.获取某个位置的字符

NSLog(@“%c”,[s8 characterAtIndex:1]);

NSString * s11 = [s8 substringFromIndex:1];

NSLog(@“%@“,s11);

NSString * s12 = [s8 substringToIndex:1];

NSLog(@“%@“,s12);

NSString * s13 = [s8 substringWithRange:NSMakRange(3,3)];

NSLog(@“%@“,s13);

NSMutableString

 

1.赋值

NSMutableString *ms1 = [NSMutableString stringWithFormat:@“456”];

NSLog(@“%@“,ms1);

2.改值或设置值

[ms1 setString:@“789”];

NSLog(@“%@“,ms1);

3.拼接

[ms1 appendString:@“123”];

NSLog(@“%@“,ms1);

[ms1 appendFormat:@“123%d”,5];

NSLog(@“%@“,ms1);

4.替换

[ms1 replaceCharatersInRange:NSMakeRange(3,3) withString:@“456”];

NSLog(@“%@“,ms1);

5.删除

[ms1 deleteCharatersInRange:NSMakeRange(9,1)];

NSLog(@“%@“,ms1);

6.插入

[ms1 insertString:@“0” atIndex:0];

NSLog(@“%@“,ms1);

7.首字母大写

NSMutableString *aa = [NSMutableString stringWithFormat:@"i love you"];

NSString *ss = [aa capitalizedString];

NSLog(@"%@",ss);

NSArray

1.初始化方法

NSArray *arr1 = [[NSArray alloc]initWithObjects:@“1”,@“2”,@“3”,nil];

NSLog(@“%@”,arr1);

2.便利构造器

NSArray *arr2 = [NSArray arrayWithObjects:@“4”,@“5”,@“6”,nil];

NSLog(@“%@“,arr2);

3.利用数组初始化数组

NSArray *arr3 = [NSArray arrayWithArray:arr2 ];

NSLog(@“%@”,arr3);

4. 字面量初始化数组

NSArray *arr4 = @[@“7”,@“8”,@“9”];

NSLog(@“%@”,arr4);

5.计算数组元素个数

NSInteger ui1 = [arr4 count];

NSLog(@“%lu”,ui1);

6.取出数组元素下标

NSINteger ui2 = [arr4 indexOfObject:@“9”];

NSLog(@“%lu”,ui2);

7.取出下标对应的元素

NSLog(@“%@“,[arr4 objectAtIndex:1]);

NSMutableArray

1.初始化数组

NSMutableArray *mArr1 = [NSMutableArray arrayWithObjects:@"1",@"2",@"3", nil];

2.添加

[mArr1 addObject:@"4"];

[mArr1 addObject:@"5"];

NSLog(@"%@",mArr1);

3.删除

[mArr1 removeLastObject];-[mArr1 removeAllObjects];//删除全部

NSLog(@"%@",mArr1);

[mArr1 removeObject:@"4"];

NSLog(@"%@",mArr1);

4.删除下标所在元素

[mArr1 removeObjectAtIndex:0];

NSLog(@"%@",mArr1);

5. 插入

[mArr1 insertObject:@"1"atIndex:0];

NSLog(@"%@",mArr1);

6.替换

[mArr1 replaceObjectAtIndex:0withObject:@"3"];

[mArr1 replaceObjectAtIndex:1 withObject:@"3"];

NSLog(@"%@",mArr1);

NSNumber  

1.将基本数据类型转换成对象类型

int i = 1;

long l = 20000;

NSNumber *number1 = [[NSNumber alloc]initWithInt:i];

2.NSNumber 类型也可以转化成int类型

int a1 = [number1 intValue];

NSLog(@"%d",a1);

NSNumber *number2 = [[NSNumber alloc]initWithLong:l];

NSLog(@"%@",number1);

NSLog(@"%@",number2);

NSString *string = @"123";

3.将字符串转化成 整型

int a2 = [string intValue];

NSLog(@"%d",a2);

4.将NSNumber转化成 字符串

[number2 stringValue];

NSLog(@"%@",number2);