ObjectC快速入門教程(3)---陣列和字典
阿新 • • 發佈:2019-02-18
一.不可變陣列
1.建立
總結:OC中陣列是物件的有序集合,陣列儲存的是物件的地址(物件的引用),不可變陣列一旦被建立,不可以繼續新增,刪除,或者修改;陣列中的元素可以為不同型別的物件.
NSArray *array1 = @[@"one", @"two", @"three", @"four", [NSNumber numberWithInt:123]];
NSLog(@"array1 = %@", array1);
NSArray *array1 = @[@"one", @"two", @"three", @"four", [NSNumber numberWithInt:123]];
NSLog(@"array1 = %@", array1);
NSArray *array2 = [[NSArray alloc]init]; //空陣列
NSLog(@"array2 = %@", array2);
NSArray *arryy3 = [[NSArray alloc]initWithObjects:@"one", @"two", nil];
NSLog(@"array3 = %@", arryy3);
2.陣列的訪問
NSLog(@"array1[1] = %@" , [array1 objectAtIndex:1]);
NSLog(@"array1[1] = %@", array1[1]);
NSLog(@"cnt = %li", [array1 count]);
//獲取元素在陣列中第一次出現的位置
NSInteger index = [array1 indexOfObject:@"two"];
NSLog(@"index = %li", index);
NSLog(@"first = %@", [array1 firstObject]); //第一個元素
NSLog (@"last = %@", [array1 lastObject]); //最後一個元素
3.陣列的比較
//陣列比較
NSArray *array10 = @[@"one", @"two", @"three"];
NSArray *array11 = [NSArray arrayWithObjects:@"one", @"two1", nil];
BOOL ret = [array10 isEqualToArray:array11]; //判斷兩個陣列是否相等
if(ret){
NSLog(@"兩個陣列相等");
}else{
NSLog(@"兩個陣列不想等");
}
//返回陣列中第一個想等的元素
id obj = [array10 firstObjectCommonWithArray:array11];
NSLog(@"%@", obj);
4.陣列排序
//陣列排序,前提:陣列中的元素是相同型別的
NSArray *sortArray = [array10 sortedArrayUsingSelector:@selector(compare:)];//@selector大於0時進行交換
NSLog(@"%@", sortArray);
5.陣列新增
//陣列新增
NSArray *array12 = [array10 arrayByAddingObject:@"five"];
NSLog(@"array12 = %@", array12);
6.指定範圍內的提取
//提取指定範圍內的陣列
NSArray *array13 = [array10 subarrayWithRange:NSMakeRange(2, 2)];
NSLog(@"array13 = %@", array13);
//NSIndexSet 下表集合類
NSMutableIndexSet *index2 = [NSMutableIndexSet indexSetWithIndex:1];
[index2 addIndex:3];
NSArray *array14 = [array10 objectsAtIndexes:index2];
NSLog(@"array14 = %@", array14);
7.字串分割成陣列
NSString* str = @"I :am :good :boy";
NSArray* array15 = [str componentsSeparatedByString:@" :"];
NSLog(@"array15 = %@", array15);
NSArray *array16 = [str componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@" :"]];
NSLog(@"array16 = %@", array16);
注意:componentsSeparatedByString
和componentsSeparatedByCharactersInSet
的區別,參考,前者以字串整體作為分隔符,後者以字串集合中的每一個字元作為分隔符.
8.陣列元素的拼接
NSArray *array = @[@"one", @"two", @"three"];
NSString *arrayStr = [array componentsJoinedByString:@" "];
NSLog(@"arrayStr = %@", arrayStr);
9.陣列遍歷
//方法1,通過陣列元素下標
for(NSInteger i = 0; i < [array count]; i++){
// NSLog(@"%@", [array objectAtIndex:i]);
}
//方法2,通過列舉器
NSEnumerator *enumerator = [array reverseObjectEnumerator];
id obj2 = nil;
while(obj2 = [enumerator nextObject]){
// NSLog(@"%@", obj2);
}
//方法3,快速列舉法
for(id obj3 in array){
NSLog(@"%@", obj3);
}
二.可變陣列
1.建立新增
NSMutableArray *marray = [[NSMutableArray alloc]initWithObjects:@"one", @"two", @"three", nil];
[marray addObject:@"four"];
[marray addObjectsFromArray:@[@"five", @"six"]]; //增加
[marray insertObject:@"zero" atIndex:0]; //插入
NSLog(@"%@", marray);
2.替換指定位置下標元素
[marray setArray:@[@"1", @"2"]];
NSLog(@"%@", marray);
[marray replaceObjectAtIndex:1 withObject:@"123"];
NSLog(@"%@", marray);
3.交換
[marray exchangeObjectAtIndex:0 withObjectAtIndex:1];
NSLog(@"%@", marray);
4.刪除
三.字典物件
1.建立,新增
NSDictionary *dict0 = @{@"one":@"1",@"two":@"2"}; //前面是key後面是value
NSLog(@"%@", dict0);
NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"one",@"1",@"two", @"2",nil];//前面是value後面是key
NSLog(@"%@", dict);
NSMutableDictionary *dict1 = [NSMutableDictionary dictionaryWithDictionary:dict0];
[dict1 setValue:@"4" forKey:@"four"]; //增加一個元素
NSInteger count = [dict1 count]; //個數
NSLog(@"%@", dict1);
id obj33 = [dict1 objectForKey:@"one"]; //根據key得到value
NSArray *keyArray = [dict1 allKeys]; //獲得所有key
NSArray *value = [dict1 allValues]; //獲得所有value
BOOL isEqual = [dict1 isEqualToDictionary:dict];
if(isEqual){
NSLog(@"相等");
}else{
NSLog(@"不相等");
}
NSLog(@"%@", value);
//增加鍵值對
[dict1 addEntriesFromDictionary:@{@"hello":@"hello123"}];
注意事項:在字典物件中,key的值是唯一的,一旦有了一個key,是不能覆蓋的。
2.字典的遍歷
//方法1,列舉法
NSEnumerator *keyEnumerator = [dict1 keyEnumerator];
id obj44 = nil;
while(obj44 = [keyEnumerator nextObject]){
NSLog(@"key = %@ value = %@", obj44, [dict1 valueForKey:obj44]);
}
//方法2,快速列舉法
for(id obj55 in dict1){
NSLog(@"key = %@ value = %@", obj55, [dict1 objectForKey:obj55]);
}