将数组分成具有相似对象的新数组 - iOS

Question

我有一个数组：包含对象的数组 A

"Anchorage, AK"
"Juneau, AK"
"Los Angeles, CA"
"Minneapolis, MS"
"Seatac, WA"
"Seattle, WA"

注意：实际的数组对象不包含引号。

如何根据字符串的最后一个字符将此数组分成多个数组？数组对我来说是否可变并不重要。

即...

Array 2 {
[1] <--- First NSArray
"Anchorage, AK"
"Jeneau, AK"

[2] <--- Second NSArray
"Los Angeles, CA"

[3] <--- Third NSArray
"Minneapolis, MS"

[4] <--- Fourth NSArray
"Seatac, WA"
"Seattle, WA"
}

在真实场景中，我不知道每个州有多少。我在想我可以在结尾处对字符串的两个字符长度部分做些什么？因为这就是我希望将它们分成本质上的状态。

Answer 1

好的 - 让我知道这是否清楚。

// Setup the inital array
NSArray *array = [[NSArray alloc] initWithObjects:@"Anchorage, AK",
                  @"Juneau, AK",
                  @"Los Angeles, CA",
                  @"Minneapolis, MS",
                  @"Seatac, WA",
                  @"Seattle, WA", nil];

// Create our array of arrays
NSMutableArray *newArray2 = [[NSMutableArray alloc] init];

// Loop through all of the cities using a for loop
for (NSString *city in array) {
    // Keep track of if we need to creat a new array or not
    bool foundCity = NO;

    // This gets the state, by getting the substring of the last two letters
    NSString *state = [city substringFromIndex:[city length] -2];

    // Now loop though our array of arrays tosee if we already have this state
    for (NSMutableArray *subArray in newArray2) {
        //Only check the first value, since all the values will be the same state
        NSString *arrayCity = (NSString *)subArray[0];
        NSString *arrayState = [arrayCity substringFromIndex:[arrayCity length] -2];

        if ([state isEqualToString:arrayState])
        {
            // Check if the states match... if they do, then add it to this array
            foundCity = YES;
            [subArray addObject:city];

            // No need to continue the for loop, so break stops looking though the arrays.
            break;
        }
    }

    // WE did not find the state in the newArray2, so create a new one
    if (foundCity == NO)
    {
        NSMutableArray *newCityArray = [[NSMutableArray alloc] initWithObjects:city, nil];
        [newArray2 addObject:newCityArray];
    }


}

//Print the results
NSLog(@"%@", newArray2);

我的输出

2014-01-20 20:28:04.787 TemperatureConverter[91245:a0b] (
        (
        "Anchorage, AK",
        "Juneau, AK"
    ),
        (
        "Los Angeles, CA"
    ),
        (
        "Minneapolis, MS"
    ),
        (
        "Seatac, WA",
        "Seattle, WA"
    )
)

Answer 2

您可以遍历原始数组和split them by delimiters 中的字符串并将它们放入新数组中。然后你可以根据数组的第二个元素查看数组和分组。