How do I check if a string contains another string in Swift?

Question

In Objective-C the code to check for a substring in an NSString is:

NSString *string = @\"hello Swift\";
NSRange textRange =[strin         


        

Answer 1

> IN SWIFT 3.0

let str = "Hello Swift"
if str.lowercased().contains("Swift".lowercased()) {
    print("String Contains Another String")
} else {
    print("Not Exists")
}

Output

String Contains Another String

Answer 2

Extension way

Swift 4

extension String {
    func contains(find: String) -> Bool{
        return self.range(of: find) != nil
    }
    func containsIgnoringCase(find: String) -> Bool{
        return self.range(of: find, options: .caseInsensitive) != nil
    }
}

var value = "Hello world"

print(value.contains("Hello")) // true
print(value.contains("bo"))    // false

print(value.containsIgnoringCase(find: "hello"))    // true
print(value.containsIgnoringCase(find: "Hello"))    // true
print(value.containsIgnoringCase(find: "bo"))       // false

---

Generally Swift 4 has contains method however it available from iOS 8.0+

---

Swift 3.1

You can write extension contains: and containsIgnoringCase for String

extension String { 

   func contains(_ find: String) -> Bool{
     return self.range(of: find) != nil
   }

   func containsIgnoringCase(_ find: String) -> Bool{
     return self.range(of: find, options: .caseInsensitive) != nil 
   }
 }

---

Older Swift version

extension String {

    func contains(find: String) -> Bool{
       return self.rangeOfString(find) != nil
     }

    func containsIgnoringCase(find: String) -> Bool{
       return self.rangeOfString(find, options: NSStringCompareOptions.CaseInsensitiveSearch) != nil
     }
}

---

Example:

var value = "Hello world"

print(value.contains("Hello")) // true
print(value.contains("bo"))    // false

print(value.containsIgnoringCase("hello"))    // true
print(value.containsIgnoringCase("Hello"))    // true
print(value.containsIgnoringCase("bo"))       // false

Answer 3

Of all of the answers here, I think they either don't work, or they're a bit of a hack (casting back to NSString). It's very likely that the correct answer to this has changed with the different beta releases.

Here is what I use:

let string: String = "hello Swift"
if string.rangeOfString("Swift") != nil
{
    println("exists")
}

The "!= nil" became required with Beta 5.

Answer 4

As of Xcode 7.1 and Swift 2.1 containsString() is working fine for me.

let string = "hello swift"
if string.containsString("swift") {
    print("found swift")
}

Swift 4:

let string = "hello swift"
if string.contains("swift") {
    print("found swift")
}

And a case insensitive Swift 4 example:

let string = "Hello Swift"
if string.lowercased().contains("swift") {
    print("found swift")
}

Or using a case insensitive String extension:

extension String {
    func containsIgnoreCase(_ string: String) -> Bool {
        return self.lowercased().contains(string.lowercased())
    }
}

let string = "Hello Swift"
let stringToFind = "SWIFT"
if string.containsIgnoreCase(stringToFind) {
    print("found: \(stringToFind)")  // found: SWIFT
}
print("string: \(string)")
print("stringToFind: \(stringToFind)")

// console output:
found: SWIFT
string: Hello Swift
stringToFind: SWIFT

Answer 5

Xcode 8/Swift 3 version:

let string = "hello Swift"

if let range = string.range(of: "Swift") {
    print("exists at range \(range)")
} else {
    print("does not exist")
}

if let lowercaseRange = string.lowercased().range(of: "swift") {
    print("exists at range \(lowercaseRange)")
} else {
    print("does not exist")
}

You can also use contains:

string.contains("swift") // false
string.contains("Swift") // true

Answer 6

You can just do what you have mentioned:

import Foundation
...
string.contains("Swift");

From the docs:

Swift’s String type is bridged seamlessly to Foundation’s NSString class. If you are working with the Foundation framework in Cocoa or Cocoa Touch, the entire NSString API is available to call on any String value you create, in addition to the String features described in this chapter. You can also use a String value with any API that requires an NSString instance.

You need to import Foundation to bridge the NSString methods and make them available to Swift's String class.