IOS Swift 2D Array Sort

Question

Using Swift i would like to sort the below array using the country name [0][1] instead of country code. Not sure how to achieve this.

let prefixCodes = [["AD", "Andorra"], ["AE", "United Arab Emirates"], ["AF", "Afghanistan"], ["AG", "Antigua & Barbuda"], ["AI", "Anguilla"], ["AL", "Albania"], ["AM", "Armenia"], ["AO", "Angola"], ["AQ", "Antarctica"], ["AR", "Argentina"], ["AS", "American Samoa"], ["AT", "Austria"], ["AU", "Australia"], ["AW", "Aruba"], ["AX", "Åland Islands"], ["AZ", "Azerbaijan"], ["BA", "Bosnia & Herzegovina"], ["BB", "Barbados"], ["BD", "Bangladesh"], ["BE", "Belgium"], ["BF", "Burkina Faso"], ["BG", "Bulgaria"], ["BH", "Bahrain"], ["BI", "Burundi"], ["BJ", "Benin"], ["BL", "St. Barthélemy"], ["BM", "Bermuda"], ["BN", "Brunei"], ["BO", "Bolivia"], ["BQ", "Caribbean Netherlands"], ["BR", "Brazil"], ["BS", "Bahamas"], ["BT", "Bhutan"], ["BV", "Bouvet Island"], ["BW", "Botswana"], ["BY", "Belarus"], ["BZ", "Belize"], ["CA", "Canada"], ["CC", "Cocos (Keeling) Islands"], ["CD", "Congo - Kinshasa"], ["CF", "Central African Republic"], ["CG", "Congo - Brazzaville"], ["CH", "Switzerland"], ["CI", "Côte d’Ivoire"], ["CK", "Cook Islands"], ["CL", "Chile"], ["CM", "Cameroon"], ["CN", "China"], ["CO", "Colombia"], ["CR", "Costa Rica"], ["CU", "Cuba"], ["CV", "Cape Verde"], ["CW", "Curaçao"], ["CX", "Christmas Island"], ["CY", "Cyprus"], ["CZ", "Czech Republic"], ["DE", "Germany"], ["DJ", "Djibouti"], ["DK", "Denmark"], ["DM", "Dominica"], ["DO", "Dominican Republic"], ["DZ", "Algeria"], ["EC", "Ecuador"], ["EE", "Estonia"], ["EG", "Egypt"], ["EH", "Western Sahara"], ["ER", "Eritrea"], ["ES", "Spain"], ["ET", "Ethiopia"], ["FI", "Finland"], ["FJ", "Fiji"], ["FK", "Falkland Islands"], ["FM", "Micronesia"], ["FO", "Faroe Islands"], ["FR", "France"], ["GA", "Gabon"], ["GB", "United Kingdom"], ["GD", "Grenada"], ["GE", "Georgia"], ["GF", "French Guiana"], ["GG", "Guernsey"], ["GH", "Ghana"], ["GI", "Gibraltar"], ["GL", "Greenland"], ["GM", "Gambia"], ["GN", "Guinea"], ["GP", "Guadeloupe"], ["GQ", "Equatorial Guinea"], ["GR", "Greece"], ["GS", "So. Georgia & So. Sandwich Isl."], ["GT", "Guatemala"], ["GU", "Guam"], ["GW", "Guinea-Bissau"], ["GY", "Guyana"], ["HK", "Hong Kong SAR China"], ["HM", "Heard & McDonald Islands"], ["HN", "Honduras"], ["HR", "Croatia"], ["HT", "Haiti"], ["HU", "Hungary"], ["ID", "Indonesia"], ["IE", "Ireland"], ["IL", "Israel"], ["IM", "Isle of Man"], ["IN", "India"], ["IO", "British Indian Ocean Territory"], ["IQ", "Iraq"], ["IR", "Iran"], ["IS", "Iceland"], ["IT", "Italy"], ["JE", "Jersey"], ["JM", "Jamaica"], ["JO", "Jordan"], ["JP", "Japan"], ["KE", "Kenya"], ["KG", "Kyrgyzstan"], ["KH", "Cambodia"], ["KI", "Kiribati"], ["KM", "Comoros"], ["KN", "St. Kitts & Nevis"], ["KP", "North Korea"], ["KR", "South Korea"], ["KW", "Kuwait"], ["KY", "Cayman Islands"], ["KZ", "Kazakhstan"], ["LA", "Laos"], ["LB", "Lebanon"], ["LC", "St. Lucia"], ["LI", "Liechtenstein"], ["LK", "Sri Lanka"], ["LR", "Liberia"], ["LS", "Lesotho"], ["LT", "Lithuania"], ["LU", "Luxembourg"], ["LV", "Latvia"], ["LY", "Libya"], ["MA", "Morocco"], ["MC", "Monaco"], ["MD", "Moldova"], ["ME", "Montenegro"], ["MF", "St. Martin"], ["MG", "Madagascar"], ["MH", "Marshall Islands"], ["MK", "Macedonia"], ["ML", "Mali"], ["MM", "Myanmar (Burma)"], ["MN", "Mongolia"], ["MO", "Macau SAR China"], ["MP", "Northern Mariana Islands"], ["MQ", "Martinique"], ["MR", "Mauritania"], ["MS", "Montserrat"], ["MT", "Malta"], ["MU", "Mauritius"], ["MV", "Maldives"], ["MW", "Malawi"], ["MX", "Mexico"], ["MY", "Malaysia"], ["MZ", "Mozambique"], ["NA", "Namibia"], ["NC", "New Caledonia"], ["NE", "Niger"], ["NF", "Norfolk Island"], ["NG", "Nigeria"], ["NI", "Nicaragua"], ["NL", "Netherlands"], ["NO", "Norway"], ["NP", "Nepal"], ["NR", "Nauru"], ["NU", "Niue"], ["NZ", "New Zealand"], ["OM", "Oman"], ["PA", "Panama"], ["PE", "Peru"], ["PF", "French Polynesia"], ["PG", "Papua New Guinea"], ["PH", "Philippines"], ["PK", "Pakistan"], ["PL", "Poland"], ["PM", "St. Pierre & Miquelon"], ["PN", "Pitcairn Islands"], ["PR", "Puerto Rico"], ["PS", "Palestinian Territories"], ["PT", "Portugal"], ["PW", "Palau"], ["PY", "Paraguay"], ["QA", "Qatar"], ["RE", "Réunion"], ["RO", "Romania"], ["RS", "Serbia"], ["RU", "Russia"], ["RW", "Rwanda"], ["SA", "Saudi Arabia"], ["SB", "Solomon Islands"], ["SC", "Seychelles"], ["SD", "Sudan"], ["SE", "Sweden"], ["SG", "Singapore"], ["SH", "St. Helena"], ["SI", "Slovenia"], ["SJ", "Svalbard & Jan Mayen"], ["SK", "Slovakia"], ["SL", "Sierra Leone"], ["SM", "San Marino"], ["SN", "Senegal"], ["SO", "Somalia"], ["SR", "Suriname"], ["SS", "South Sudan"], ["ST", "São Tomé & Príncipe"], ["SV", "El Salvador"], ["SX", "Sint Maarten"], ["SY", "Syria"], ["SZ", "Swaziland"], ["TC", "Turks & Caicos Islands"], ["TD", "Chad"], ["TF", "French Southern Territories"], ["TG", "Togo"], ["TH", "Thailand"], ["TJ", "Tajikistan"], ["TK", "Tokelau"], ["TL", "Timor-Leste"], ["TM", "Turkmenistan"], ["TN", "Tunisia"], ["TO", "Tonga"], ["TR", "Turkey"], ["TT", "Trinidad & Tobago"], ["TV", "Tuvalu"], ["TW", "Taiwan"], ["TZ", "Tanzania"], ["UA", "Ukraine"], ["UG", "Uganda"], ["UM", "U.S. Outlying Islands"], ["US", "United States"], ["UY", "Uruguay"], ["UZ", "Uzbekistan"], ["VA", "Vatican City"], ["VC", "St. Vincent & Grenadines"], ["VE", "Venezuela"], ["VG", "British Virgin Islands"], ["VI", "U.S. Virgin Islands"], ["VN", "Vietnam"], ["VU", "Vanuatu"], ["WF", "Wallis & Futuna"], ["WS", "Samoa"], ["YE", "Yemen"], ["YT", "Mayotte"], ["ZA", "South Africa"], ["ZM", "Zambia"], ["ZW", "Zimbabwe"]]

Thank you in advance.

Have you tried any code using Swift's inbuilt array sort function? — Paulw11
– Paulw11, Commented Mar 18, 2016 at 8:27
not sure how to use this one. prefixCodes.sort { (<#[String]#>, <#[String]#>) -> Bool in <#code#> } — Kanan Jarrus
– Kanan Jarrus, Commented Mar 18, 2016 at 8:32
See the description of the sort closure here - developer.apple.com/library/ios/documentation/Swift/Conceptual/… — Paulw11
– Paulw11, Commented Mar 18, 2016 at 8:41

ronatory · Accepted Answer · 2016-03-18 08:55:44Z

1

With sort and the shorthand arguments you can order the second element in your 2D array like this:

let sortedAfterCountryNames = prefixCodes.sort{ $0[1] < $1[1] }

print(sortedAfterCountryNames)
// [["AF", "Afghanistan"], ["AL", "Albania"], ["DZ", "Algeria"], ["AS", "American Samoa"], ...

edited Mar 18, 2016 at 8:55

answered Mar 18, 2016 at 8:41

ronatory

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2 Comments

Kanan Jarrus Over a year ago

Thank you very much. Thats exactly what i was looking for.

ronatory Over a year ago

Nice, that I could help you. I added some further informations and a link for more details about closures, the sort method and the short hand arguments

Muzahid · Accepted Answer · 2016-03-18 08:54:04Z

1

Hope this will help you.

let sortedArray = prefixCodes.sort { (first, second) -> Bool in
  return first.last < second.last
}

answered Mar 18, 2016 at 8:54

Muzahid

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Comments

Sweeper · Accepted Answer · 2016-03-18 08:58:34Z

You should use the sort method to sort your array.

Let's first create an unsorted array:

var arr = [["A", "Hello world"], 
    ["C", "Bye world"], 
    ["B", "idk what to say here"]]

Now let's look at what arguments the sort method needs. Apparently it needs a closure of the following signature:

([String], [String]) -> Bool

The most straightforward (but not so swifty) approach would be to write a function with that signature:

func myFunction (first: [String], second: [String]) -> Bool {

}

In that function, you need to decide whether the algorithm should swap the two arguments. If it should not, return true, otherwise false. I think if you want to sort in alphabetical order, you should just compare the two strings

return first[1] < second[1]

You access the element at index 1 because that is where you store the country names, right?

Then, call sort with the function

arr = arr.sort(myFunction)

However, that is not very swifty. To make this the most swifty, you can do this:

arr.sort {
    $0[1] < $1[1]
}

Much better!

Valentin · Accepted Answer · 2016-03-18 12:32:18Z

0

You may do the following:

prefixCodes.sort { $0[1] < $1[1] }

But to be safer, I think that you should define a Country struct like this:

struct Country {
    let code: String
    let name: String

    init(_ code: String, _ name: String) {
        self.code = code
        self.name = name
    }
}

let countries = [Country("AD", "Andorra"), Country("AE", "United Arab Emirates"), Country("BQ", "Caribbean Netherlands")]

print(countries.sort { $0.name < $1.name })

So that if you want to add more details to your countries, you will not have a chance to break your sort closure.

Or if you want to keep things simple but still enforce strong typing, you could use tuples:

let countries = [("AD", "Andorra"), ("AE", "United Arab Emirates"), ("BQ", "Caribbean Netherlands")]

print(countries.sort { $0.1 < $1.1 })

If you mix different tuple lengths in your array:

let countries = [("AD", "Andorra"), ("toto"), ("tata", "titi", "tutu")]

Swift will return this error:

error: type of expression is ambiguous without more context

edited Mar 18, 2016 at 12:32

answered Mar 18, 2016 at 8:53

Valentin

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1 Comment

Valentin Over a year ago

I added a tuple solution which lets Swift ensure that all members of your array have the same size, without having to declare a struct or using a constructor. If my answer was helpful, you may want to upvote it, thanks.

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