数组和可变数组的基本用法
NSString *st1 = @"158";
NSString *str2 = @"39";
int a = [st1 intValue];
int b = [str2 intValue];
int result = a - b;
NSString *str = [NSString stringWithFormat:@"%d", result];
NSLog(@"str is %@", str);
NSString *string = @"123-456-789-000";
//方法一
// NSString *sub1 = [string substringWithRange:NSMakeRange(0, 3)];
// NSString *sub2 = [string substringWithRange:NSMakeRange(4, 3)];
// NSString *sub3 = [string substringWithRange:NSMakeRange(8, 3)];
// NSString *sub4 = [string substringWithRange:NSMakeRange(12, 3)];
// NSString *resultStr = [NSString stringWithFormat:@"%@%@%@%@", sub1, sub2, sub3, sub4];
// NSLog(@"resultStr is %@", resultStr);
//方法二
// NSString *resultStr = [string stringByReplacingOccurrencesOfString:@"-" withString:@""];
// NSLog(@"resultStr is %@", resultStr);
NSArray *array = [string componentsSeparatedByString:@"-"];
NSString *newString = [array componentsJoinedByString:@""];
NSLog(@"newString-------------------%@",newString);
//方法三
NSArray *arr = [string componentsSeparatedByString:@"-"];
NSString *resultStr = [arr componentsJoinedByString:@""];
NSLog(@"resultStr is %@", resultStr);
}
return 0;
}
/***************NSMutableArray***************/
//使用父类的构造方法创建一个可变数组
// NSMutableArray *arr = [NSMutableArray array];
//NSMutableArray自己的构造方法,initWithCapacity表示初始化数组的容量大小，注意：不能限制容量大小,只是提高代码的可读性
NSMutableArray *arr0 = [[NSMutableArray alloc] initWithCapacity:5];
NSMutableArray *ar0 = [NSMutableArray array];
[ar0 addObject:@"3234224142424"];
NSLog(@"ar0-----------%@",ar0);
NSMutableArray *ar1 = [NSMutableArray arrayWithArray:ar0];
NSLog(@"ar1-----------%@",ar1);
NSMutableArray *ar2 = [NSMutableArray arrayWithObjects:ar0,ar1, nil];
NSLog(@"ar2-----------%@",ar2);
//添加元素(对象)
[arr0 addObject:@"1"];
[arr0 addObject:@"2"];
[arr0 addObject:@"3"];
[arr0 addObject:@"4"];
NSLog(@"arr0 is %@", arr0);
//用父类的构造器
NSMutableArray *arr1 = [NSMutableArray arrayWithObjects:@"1", @"3", nil];
NSLog(@"arr1 is %@", arr1);
//插入元素
[arr1 insertObject:@"2" atIndex:1];
[arr1 insertObject:@"0" atIndex:0];
NSLog(@"arr1 is %@", arr1);
//删除元素
[arr1 removeLastObject];
NSLog(@"arr1 is %@", arr1);
//删除指定下标元素
[arr1 removeObjectAtIndex:0];
NSLog(@"arr1 is %@", arr1);
//删除指定元素//如果元素不在数组中，则什么也不做
[arr1 removeObject:@"3"];
NSLog(@"arr1 is %@", arr1);
//删除所有元素
[arr1 removeAllObjects];
NSLog(@"arr1 is %@", arr1);
//添加多个元素
NSMutableArray *arr2 = [NSMutableArray arrayWithObjects:@"1", @"2", @"3", nil];
NSArray *lists = @[@"4", @"5", @"6"];
[arr2 addObjectsFromArray:lists];
NSLog(@"arr2 is %@", arr2);
//替换和交换元素
//根据传过来的对象替换下标对象
[arr2 replaceObjectAtIndex:arr2.count - 1 withObject:@"7"];
NSLog(@"arr2 is %@", arr2);
//根据两个元素的下标交换元素
[arr2 exchangeObjectAtIndex:0 withObjectAtIndex:arr2.count - 1];
NSLog(@"arr2 is %@", arr2);
//数组的遍历
// for (int i = 0; i < arr2.count; i++) {
// NSString *obj = [arr2 objectAtIndex:i];
// NSLog(@"arr2[%d] is %@", i, obj);
// }
//快速便利
for (NSString *obj in arr2) {
//循环块
NSLog(@"arr2[%ld] is %@", [arr2 indexOfObject:obj], obj);
}
