divided into sections alphabetic my Tableview

Question

i have an array that contains name in string format (es.luca,marco,giuseppe,..). This array will be used to fill the table. how can I divide the table into sections (az) and put in the name of the array inside the right section?

Answer 1

You can iterate through the array to create a dictionary with the first letter as the key and an array of names as a value:

In Swift

var nameDictionary: Dictionary<String, Array<String>> = [:]

for name in nameArray {
    var key = name[0].uppercaseString // first letter of the name is the key
    if let arrayForLetter = nameDictionary[key] { // if the key already exists
        arrayForLetter.append(name) // we update the value
        nameDictionary.updateValue(arrayForLetter, forKey: key) // and we pass it to the dictionary
    } else { // if the key doesn't already exists in our dictionary
        nameDictionary.updateValue([name], forKey: key) // we create an array with the name and add it to the dictionary
    }
}

In Obj-C

NSMutableDictionary *nameDictionary = [[NSMutableDictionary alloc] init];

for name in nameArray {

    NSString *key =  [[name substringToIndex: 1] uppercaseString];

    if [nameDictionary objectForKey:key] != nil {

         NSMutableArray *tempArray = [nameDictionary objectForKey:key];
        [tempArray addObject: name];
        [nameDictionary setObject:tempArray forkey:key];
    } else {
        NSMutableArray *tempArray = [[NSMutableArray alloc] initWithObjects: name, nil];
        [nameDictionary setObject:tempArray forkey:key];
    }
}

then you can get your number of sections by using nameDictionary.count, the number of rows by getting nameDictionary[key].count and the content of your rows in a particular section with nameDictionary[key] which will return an array of all the names starting with the letter stored in key

EDIT: couple that with Piterwilson answer to have a full answer

EDIT 2: added Obj-C code

Notice: As I'm not on my mac, there might be small errors in the code but the principle remains the same