I have the following dictionary:
["uno" : "unoValue", "dos" : "dosValue", "tres" : "tresValue"]
I need to do a each of the keys that contain certain characters. For example if I look for 'no' I would only get key "uno" because of the "uNOValue". If I look for 'val' I would get all three keys.
I would need to get all the keys in an array such as ["uno"] and ["uno","dos","tres"] for the second case.
I am new at swift but I am building a dummy app for a search and I have no idea how to do this. If you have any other ideas for the search function I will also accept them gratefully.
dict = {"uno" : "unoValue", "dos" : "dosValue", "tres" : "tresValue"}
search_term = "Val"
list = []
for key, value in dict.items():
if search_term in value:
list.append(key)
print (list)
Try this:
let dict = ["uno" : "unoValue", "dos" : "dosValue", "tres" : "tresValue"]
let searchTerm = "val"
let keys = Array(
dict.keys.filter { dict[$0]!.range(of: searchTerm, options: [.caseInsensitive]) != nil }
)
print(keys)
How it works:
dict.keys.filter filter all the keys in the dictionary meeting a certain condition
dict[$0]!.range(of: searchTerm, options: [.caseInsensitive]) != nil checks the value that it contains the search term
Array( ... ) converts it to an array of strings, otherwise it's a LazyFilterCollection
my Playground sample:
import Foundation
let dict = ["uno" : "unoValue", "dos" : "dosValue", "tres" : "tresValue"]
let searchTerm = "val"
var result = dict.filter {
$0.value.range(of: searchTerm, options: [.caseInsensitive]) != nil
}.map{$0.key}
print(result) // ["tres", "uno", "dos"]
Related
struct Test {
var title: String
var message: [String?: String?]
init(title: String, message: [String?:String?]) {
self.title = title
self.message = message
}
}
var cases = [
Test(title: "1", message: ["tag1": nil]),
Test(title: "2", message: ["tag2": "preview2"]),
Test(title: "3", message: [nil:nil]),
Test(title: "4", message: ["tag1":"preview4"])
]
Now, I want:
An array with all keys from message property from cases - tag1 and tag2 (no nils in it). I just tried everything I know, I couldn't do it. Tried with filtering cases, got optionals.
There are no previews without a tag, so there is no need for an array with them. I only need a list with the tags, in order to sort it and show the relevant previews from the cases. That's why I need to know a way how to access these previews from the cases. Let's say in a UITableView:
cell.previewLabel?.text = cases[indexPath.row].preview[//No idea what here]
Of course, a dictionary with [tags: previews] would also be perfect!
Thanks in advance! I hope what I want is possible.
Here is an array that only contains elements from cases that have all keys and values not nil :
let filtered = cases.filter { test in
return test.message.allSatisfy({ entry in
return entry.key != nil && entry.value != nil
})
}
Or using the shorthand notation :
let filtered = cases.filter {
$0.message.allSatisfy({
$0.key != nil && $0.value != nil
})
}
With structs there is a default initializer, so you can write your Test struct this way:
struct Test {
var title: String
var message: [String?: String?]
}
It's not completely clear to me what you're attempting to do, however, this will filter your cases array to only Test objects that contain non-nil values in the message dictionary:
let nonNil = cases.filter { (test) -> Bool in
return Array(test.message.values).filter({ (value) -> Bool in
return value == nil
}).count <= 0
}
The variable nonNil now contains the Test objects where title is "2" and title is "4".
You could further filter that if you want a [tags:preview] dictionary. Something like this would do that:
let tags = nonNil.map( { $0.message} ).flatMap { $0 }.reduce([String:String]()) { (accumulator, current) -> [String:String] in
guard let key = current.key, let value = current.value else { return accumulator }
var accum = accumulator
accum.updateValue(value, forKey: key)
return accum
}
The tags dictionary now contains: ["tag1": "preview4", "tag2": "preview2"]
I have a array of tuples like the following
var customProducts = [(productType: String, info:[String:AnyObject?])]
The parameter "productType" works like a "product category", like fruits, grains, beverage, etc.
The parameter "info" is a dictionary of nutritional information of the product.
I want to get a subset of the tuples array, based on the productType so I could obtain just the "info" dictionary for an specific productType. In C# I would try something like the following using Linq:
var fruits = customProducts.Where(q=>q.productType == "fruit").Select(q => q.info) as List<KeyValuePair<string, object>>;
How may I archive the same results using Swift (2.x)?
Thanks!
I think the Swift equivalent would be:
let fruits = customProducts.filter { $0.productType == "fruit" }.map { $0.info }
Here fruits is [[String : AnyObject?]], an array of dictionaries (an array of info, the same as your List<KeyValuePair<string, object>> if I'm not mistaken).
You can use the filter method
let beverageInfo = (customProducts.filter { $0.productType == "Beverage" }).first?.info
Now beverageInfo is [String : AnyObject?]?, an optional dictionary representing the info for "Beverage" tuple.
You should filter the array according to what type the product is
Eg
var customProducts = [(productType: String, info:[String:AnyObject?])]
let fruitProducts = customProducts.filter { product in
if product.productType == "fruit" {
return true
} else {
return false
}
}.map { $0.info }
Then you can use fruitProducts however you want.
What woudl be a simple way to reduce a string like AAA:111;BBB:222;333;444;CCC:555 to a dictionary in Swift. I have the following code:
var str = "AAA:111;BBB:222;333;444;CCC:555"
var astr = str.componentsSeparatedByString(";").map { (element) -> [String:String] in
var elements = element.componentsSeparatedByString(":")
if elements.count < 2 {
elements.insert("N/A", atIndex: 0)
}
return [elements[0]:elements[1]]
}
The code above produces an Array of Dictionaries:
[["A": "111"], ["BBB": "222"], ["UKW": "333"], ["UKW": "444"], ["CCC": "555"]]
I want it to produce
["A": "111", "BBB": "222", "UKW": "333", "UKW": "444", "CCC": "555"]
but no mater what I try, since i call the map function on an Array it seems impossible to convert the nature of the map function's result.
NOTE: The dictionary in string format is described as either having KEY:VALUE; format or VALUE; format, in which case the mapping function will add the "N/A" as being the key of the unnamed value.
Any help on this matter is greatly appreciated.
Your map produces an array of dictionaries. When you want to combine them into 1, that's a perfect job for reduce:
func + <K,V>(lhs: Dictionary<K,V>, rhs: Dictionary<K,V>) -> Dictionary<K,V> {
var result = Dictionary<K,V>()
for (key, value) in lhs {
result[key] = value
}
for (key, value) in rhs {
result[key] = value
}
return result
}
var str = "AAA:111;BBB:222;333;444;CCC:555"
var astr = str
.componentsSeparatedByString(";")
.reduce([String: String]()) {
aggregate, element in
var elements = element.componentsSeparatedByString(":")
if elements.count < 2 {
elements.insert("N/A", atIndex: 0)
}
return aggregate + [elements[0]:elements[1]]
}
print(astr)
Swift has no default operator to "combine" two Dictionaries so you have to define one. Note that the + here is not commutative: dictA + dictB != dictB + dictA. If a key exist in both dictionaries, the value from the second dictionary will be used.
This is a work for reduce:
let str = "AAA:111;BBB:222;333;444;CCC:555"
let keyValueStrings = str.componentsSeparatedByString(";")
let dictionary = keyValueStrings.reduce([String: String]()) {
aggregate, element in
var newAggregate = aggregate
let elements = element.componentsSeparatedByString(":")
let key = elements[0]
// replace nil with the value you want to use if there is no value
let value = (elements.count > 1) ? elements[1] : nil
newAggregate[key] = value
return newAggregate
}
print(dictionary)
You can also make aggregate mutable directly:
let dictionary = keyValueStrings.reduce([String: String]()) {
(var aggregate: [String: String], element: String) -> [String: String] in
let elements = element.componentsSeparatedByString(":")
let key = elements[0]
// replace nil with the value you want to use if there is no value
let value = (elements.count > 1) ? elements[1] : nil
aggregate[key] = value
return aggregate
}
This is a functional approach, but you can achieve the same using a for iteration.
The reason this is happening is because map can only return arrays. If you are using this method to parse your string, then you need to convert it to a dictionary after.
var newDict = [String:String]()
for x in astr {
for (i, j) in x {
newDict[i] = j
}
}
The current issue with your code is that map function iterates over array containing [["key:value"],["key:value"]..] and you separate it again. But it returns ["key":"value"] which you then add to your array.
Instead you can add elements[0]:elements[1] directly to a locally kept variable which will fix your problem. Something like
finalVariable[elements[0]] = elements[1]
I have an array containing a number of strings. I have used contains() (see below) to check if a certain string exists in the array however I would like to check if part of a string is in the array?
itemsArray = ["Google, Goodbye, Go, Hello"]
searchToSearch = "go"
if contains(itemsArray, stringToSearch) {
NSLog("Term Exists")
}
else {
NSLog("Can't find term")
}
The above code simply checks if a value is present within the array in its entirety however I would like to find "Google, Google and Go"
Try like this.
let itemsArray = ["Google", "Goodbye", "Go", "Hello"]
let searchToSearch = "go"
let filteredStrings = itemsArray.filter({(item: String) -> Bool in
var stringMatch = item.lowercaseString.rangeOfString(searchToSearch.lowercaseString)
return stringMatch != nil ? true : false
})
filteredStrings will contain the list of strings having matched sub strings.
In Swift Array struct provides filter method, which will filter a provided array based on filtering text criteria.
First of all, you have defined an array with a single string.
What you probably want is
let itemsArray = ["Google", "Goodbye", "Go", "Hello"]
Then you can use contains(array, predicate) and rangeOfString() – optionally with
.CaseInsensitiveSearch – to check each string in the array
if it contains the search string:
let itemExists = contains(itemsArray) {
$0.rangeOfString(searchToSearch, options: .CaseInsensitiveSearch) != nil
}
println(itemExists) // true
Or, if you want an array with the matching items instead of a yes/no
result:
let matchingTerms = filter(itemsArray) {
$0.rangeOfString(searchToSearch, options: .CaseInsensitiveSearch) != nil
}
println(matchingTerms) // [Google, Goodbye, Go]
Update for Swift 3:
let itemExists = itemsArray.contains(where: {
$0.range(of: searchToSearch, options: .caseInsensitive) != nil
})
print(itemExists)
let matchingTerms = itemsArray.filter({
$0.range(of: searchToSearch, options: .caseInsensitive) != nil
})
print(matchingTerms)
Try like this.
Swift 3.0
import UIKit
let itemsArray = ["Google", "Goodbye", "Go", "Hello"]
var filterdItemsArray = [String]()
func filterContentForSearchText(searchText: String) {
filterdItemsArray = itemsArray.filter { item in
return item.lowercased().contains(searchText.lowercased())
}
}
filterContentForSearchText(searchText: "Go")
print(filterdItemsArray)
Output
["Google", "Goodbye", "Go"]
In Swift 5 with better readability :
let itemsArray = ["Google", "Goodbye", "Go", "Hello"]
let searchString = "Googled"
let result = itemsArray.contains(where: searchString.contains)
print(result) //prints true in the above case.
MARK:- Swift 5, Swift 4
//MARK:- You will find the array when its filter in "filteredStrings" variable you can check it by count if count > 0 its means you have find the results
let itemsArray = ["Google", "Goodbye", "Go", "Hello"]
let searchToSearch = "go"
let filteredStrings = itemsArray.filter({(item: String) -> Bool in
let stringMatch = item.lowercased().range(of: searchToSearch.lowercased())
return stringMatch != nil ? true : false
})
print(filteredStrings)
if (filteredStrings as NSArray).count > 0
{
//Record found
//MARK:- You can also print the result and can do any kind of work with them
}
else
{
//Record Not found
}
func filterContentForSearchText(_ searchText: String) {
filteredString = itemsArray.filter({( item : String) -> Bool in
return item.lowercased().contains(searchText.lowercased())
})
}
In Swift 4:
let itemsArray = ["Google", "Goodbye", "Go", "Hello"]
let searchString = "Go"
let filterArray = itemsArray.filter({ { $0.range(of: searchString, options: .caseInsensitive) != nil}
})
print(filterArray)
I had the same problem recently, didn't like most of these answers,
solved it like this:
let keywords = ["doctor", "hospital"] //your array
func keywordsContain(text: String) -> Bool { // text: your search text
return keywords.contains { (key) -> Bool in
key.lowercased().contains(text.lowercased())
}
}
This will also correctly trigger searches like "doc", which many of the above answers do not and is best practice.
contains() is more performant than first() != nil
source: https://www.avanderlee.com/swift/performance-collections/
If you are just checking if an item exists in a specific array, try this:
var a = [1,2,3,4,5]
if a.contains(4) {
print("Yes, it does contain number 4")
}
else {
print("No, it doesn't")
}
I have an array with data for my TableView sections
let menuItems : Dictionary<String,Dictionary<String,String>>[] = [
[
"data" : [
"name":"test",
"image":"test.png"
]
],
[
"data" : [
"name":"test2",
"image":"test2.png"
]
]
]
I'm trying to access it by using subscript
func tableView(tableView: UITableView!, titleForHeaderInSection section: Int) -> String! {
return menuItems[section]["data"]["name"]
}
and have the error
Could not find member 'subscript'
I have read a lot of similar questions on stackoverflow, but still haven't understood how to fix it. I tried to unwrap with "!" symbol and used another variables - no result.
Could you explain how does it works, please?
println(menuItems[0]["data"]!["name"])
Short answer: menuItems[0]["data"] returns an optional dictionary.
You can look at the below REPL output to understand the issue.
sets up the object.
shows that the array returns a regular dictionary. If the index is out of range, an error will be thrown instead of returning an optional dictionary.
shows that accessing a key in a dictionary that does not exist will return nil
shows that accessing a key in a dictionary will return an optional of its value type. For instance, if a dictionary is storing Strings in its values, it will return a String? when indexed into.
shows that we cannot use subscripts on an optional dictionary.
shows that we can force the optional dictionary to be a dictionary because we know it is not nil. The REPL shows us that the new return type is Dictionary<String, String>
shows that we can then use subscripts to get at the innermost values, and this returns an optional string to us. Optional strings are printable, so my code above doesn't need a second !.
shows that if we force both dictionary return types to their non-optional types, we get a regular value back (a string).
In real code, you would probably want to check for optionals, and handle nils accordingly.
1> let menu: Dictionary<String, Dictionary<String, String>>[] = [["dict1" : ["key" : "val"]], ["dict2" : ["key" : "val"]]]
menu: Dictionary<String, Dictionary<String, String>>[] = size=2 {
[0] = {
[0] = {
key = "dict1"
value = {
[0] = {
key = "key"
value = "val"
}
}
}
}
[1] = {
[0] = {
key = "dict2"
value = {
[0] = {
key = "key"
value = "val"
}
}
}
}
}
2> menu[0]
$R1: Dictionary<String, Dictionary<String, String>> = {
[0] = {
key = "dict1"
value = {
[0] = {
key = "key"
value = "val"
}
}
}
}
3> menu[0]["key"]
$R2: Dictionary<String, String>? = nil
4> menu[0]["dict1"]
$R3: Dictionary<String, String>? = Some {
[0] = {
key = "key"
value = "val"
}
}
5> menu[0]["dict1"]["key"]
REPL:6:1: error: could not find member 'subscript'
menu[0]["dict1"]["key"]
^~~~~~~~~~~~~~~~~~~~~~~
6> menu[0]["dict1"]!
$R4: Dictionary<String, String> = {
[0] = {
key = "key"
value = "val"
}
}
7> menu[0]["dict1"]!["key"]
$R5: String? = "val"
8> menu[0]["dict1"]!["key"]!
$R6: String = "val"