Question

var sections : [(index: Int, length :Int, title: String)] = Array()
var array = ["Moscow", "Saint Petersburg", "Novosibirsk", "Novosibirsk", "Nizhny Novgorod", "Samara", "Omsk", "Kiyv", "Odessa", "Donetsk", "Harkiv", "Lviv", "Uzhgorod", "Zhytomyr", "Luhansk", "Mikolayv", "Kherson", "Germany", "Berlin", "Hamburg", "Munich", "Cologne", "Frankfurt", "Stuttgart", "Düsseldorf", "Dortmund", "Essen", "Bremen", "Abilene", "Akron", "Albuquerque", "Alexandria", "Allentown", "Amarillo", "Anaheim", "Anchorage", "Ann Arbor", "Antioch", "Arlington", "Arvada", "Athens", "Atlanta", "Augusta", "Aurora", "Austin", "Bakersfield", "Baltimore", "Baton Rouge", "Beaumont", "Bellevue", "Berkeley", "Billings", "Birmingham", "Boise", "Boston", "Boulder", "Bridgeport", "Broken Arrow", "Brownsville", "Buffalo", "Burbank", "Cambridge", "Cape Coral", "Carlsbad", "Carrollton", "Cary", "Cedar Rapids", "Centennial", "Chandler", "Charleston", "Charlotte", "Chattanooga", "Chesapeake", "Chicago", "Chula Vista", "Cincinnati", "Clarksville", "Clearwater", "Cleveland", "College Station", "Colorado Springs", "Columbia", "Columbus", "Concord", "Coral Springs", "Corona", "Corpus Christi", "Costa Mesa", "Dallas", "Daly City", "Davenport", "Dayton", "Denton", "Denver", "Des Moines", "Detroit", "Downey", "Durham", "Edison", "El Cajon", "El Monte", "El Paso", "Elgin", "Elizabeth", "Elk Grove", "Erie", "Escondido", "Eugene", "Evansville", "Everett", "Fairfield", "Fargo", "Fayetteville", "Fontana", "Fort Collins", "Fort Lauderdale", "Fort Wayne", "Fort Worth", "Fremont", "Fresno", "Frisco", "Fullerton", "Gainesville", "Garden Grove", "Garland", "Gilbert", "Glendale", "Grand Prairie", "Grand Rapids", "Green Bay", "Greensboro", "Gresham", "Hampton", "Hartford", "Hayward", "Henderson", "Hialeah", "High Point", "Hollywood", "Honolulu", "Houston", "Huntington Beach", "Huntsville", "Independence", "Indianapolis", "Inglewood", "Irvine", "Irving", "Jackson", "Jacksonville", "Jersey City", "Joliet", "Kansas City", "Kent", "Killeen", "Knoxville", "Lafayette", "Lakeland", "Lakewood", "Lancaster", "Lansing", "Laredo", "Las Cruces", "Las Vegas", "Lewisville", "Lexington", "Lincoln", "Little Rock", "Long Beach", "Los Angeles", "Louisville", "Lowell", "Lubbock", "Madison", "Manchester", "McAllen", "McKinney", "Memphis", "Mesa", "Mesquite", "Miami", "Miami Gardens", "Midland", "Milwaukee", "Minneapolis", "Miramar", "Mobile", "Modesto", "Montgomery", "Moreno Valley", "Murfreesboro", "Murrieta", "Naperville", "Nashville", "New Haven", "New Orleans", "New York", "Newark", "Newport News", "Norfolk", "Norman", "North Charleston", "North Las Vegas", "Norwalk", "Oakland", "Oceanside", "Oklahoma City", "Olathe", "Omaha", "Ontario", "Orange", "Orlando", "Overland Park", "Oxnard", "Palm Bay", "Palmdale", "Pasadena", "Paterson", "Pearland", "Pembroke Pines", "Peoria", "Peoria", "Philadelphia", "Phoenix", "Pittsburgh", "Plano", "Pomona", "Pompano Beach", "Port St. Lucie", "Portland", "Providence", "Provo", "Pueblo", "Raleigh", "Rancho Cucamonga", "Reno", "Rialto", "Richardson", "Richmond", "Riverside", "Rochester", "Rockford", "Roseville", "Round Rock", "Sacramento", "Saint Paul", "Salem", "Salinas", "Salt Lake City", "San Antonio", "San Bernardino", "San Diego", "San Francisco", "San Jose", "San Mateo", "Santa Ana", "Santa Clara", "Santa Clarita", "Santa Maria", "Santa Rosa", "Savannah", "Scottsdale", "Seattle", "Shreveport", "Simi Valley", "Sioux Falls", "South Bend", "Spokane", "Springfield", "St. Louis", "St. Petersburg", "Stamford", "Sterling Heights", "Stockton", "Sunnyvale", "Surprise", "Syracuse", "Tacoma", "Tallahassee", "Tampa", "Temecula", "Tempe", "Thornton", "Thousand Oaks", "Toledo", "Topeka", "Torrance", "Tucson", "Tulsa", "Tyler", "Vallejo", "Vancouver", "Ventura", "Victorville", "Virginia Beach", "Visalia", "Waco", "Warren", "Washington", "Waterbury", "West Covina", "West Jordan", "West Palm Beach", "West Valley City", "Westminster", "Wichita", "Wichita Falls", "Wilmington", "Winston–Salem", "Woodbridge", "Worcester", "Yonkers", "York"]
override func viewDidLoad() {
    array.sort { $0 < $1 }
    var index = 0;

    for ( var i = 0; i < array.count; i++ ) {

        let commonPrefix = array[i].commonPrefixWithString(array[index], options: .CaseInsensitiveSearch)

        if (countElements(commonPrefix) == 0 ) {

            let string = array[index].uppercaseString;

            let firstCharacter = string[string.startIndex]

            let title = "\(firstCharacter)"

            let newSection = (index: index, length: i - index, title: title)

            sections.append(newSection)

            index = i;

        }

    }
}


override func numberOfSectionsInTableView(tableView: UITableView) -> Int {

    return sections.count

}

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

    return sections[section].length

}

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

    var cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell;

    cell.textLabel?.text = array[sections[indexPath.section].index + indexPath.row]

    return cell

}

override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String {

    return sections[section].title

}

override func sectionIndexTitlesForTableView(tableView: UITableView) -> [AnyObject]! {

    return sections.map { $0.title }

}


override func tableView(tableView: UITableView, sectionForSectionIndexTitle title: String, atIndex index: Int) -> Int {

    return index

}

我在this网站上找到了一个例子。但是，我不知道在if情况下countElements()是什么。他没有宣布。有人可以帮忙吗？非常感谢你。

Answer 1

使用此：

if (commonPrefix.characters.count == 0 )

现在不推荐使用通用前缀。

Answer 2

对于那些想要Swfit 4+的更新版本的人

                      var index = 0;
          // for ( var i = 0; i < array.count; i++ )
        for i in 0..<(array.count - 1)
           {

               let commonPrefix = array[i].commonPrefix(with: array[index], options: .caseInsensitive)


            if (commonPrefix.count == 0 ) {

                   let string = array[index].uppercased();

                   let firstCharacter = string[string.startIndex]

                   let title = "\(firstCharacter)"

                   let newSection = (index: index, length: i - index, title: title)

                   sections.append(newSection)

                   index = i;

               }

           }

尽管我仍然无法100％正常工作，但我认为我的建议可能不正确

uitableview与按字母顺序索引（swift）

2 个答案: