How to Compare Two Strings Ignoring Case in Swift Language

How to compare two strings ignoring case in Swift language?

Try this:

var a = "Cash"
var b = "cash"
let result: NSComparisonResult = a.compare(b, options: NSStringCompareOptions.CaseInsensitiveSearch, range: nil, locale: nil)

// You can also ignore last two parameters(thanks 0x7fffffff)
//let result: NSComparisonResult = a.compare(b, options: NSStringCompareOptions.CaseInsensitiveSearch)

result is type of NSComparisonResult enum:

enum NSComparisonResult : Int {

    case OrderedAscending
    case OrderedSame
    case OrderedDescending
}

So you can use if statement:

if result == .OrderedSame {
    println("equal")
} else {
    println("not equal")
}

Non-case-sensitive switch statement in swift?

You could uppercase text (or lowercase [lowercased()] as mentioned in the comments), so case would not matter:

switch text.uppercased() {
case "HI", "HELLO", "GOOD DAY":
  return "Hello, sir."
default:
  return "Sorry, I didn't understand!"
}

Compare two strings?]

if "test".contains("es") {
    //...                
}

Case insensitive comparison NSString

if( [@"Some String" caseInsensitiveCompare:@"some string"] == NSOrderedSame ) {
  // strings are equal except for possibly case
}

The documentation is located at Search and Comparison Methods

Check if a string exists in an array case insensitively

you can use

word.lowercaseString 

to convert the string to all lowercase characters

How to compare two Strings to check if they have same Characters Swift 4?

If “multiplicity” counts (i.e. "aab" has the same characters as "aba",
but not the same characters as "abb"), then

s1.sorted() == s2.sorted()

does the trick. If you don't care about the multiplicity, then just

Set(s1) == Set(s2)

Example:

let firstArray = ["sumit", "ambuj", "abhi", "aba"]
let secondArray = ["mitsu", "jumba", "hibb", "abb"]

for (s1, s2) in zip(firstArray, secondArray) {
    print(s1.sorted() == s2.sorted())
}

// true, true, false, false

for (s1, s2) in zip(firstArray, secondArray) {
    print(Set(s1) == Set(s2))
}

// true, true, false, true

For longer strings it might be more efficient to maintain a
dictionary with the number of occurrences of each character in
a string (similar to a NSCountedSet):

func characterCounts(_ s: String) -> [Character: Int] {
    return s.reduce(into: [:], { $0[$1, default: 0] += 1 })
}

and then compare the dictionaries:

characterCounts(s1) == characterCounts(s2)

case insensitive matching search in string array swift 3

You can try with localizedCaseInsensitiveContains

let filteredArray = self.arrCountry.filter { $0.localizedCaseInsensitiveContains("india") }

Comparing String ignoring spaces at the beginning or ending

 NSString *string1 = @" Hello";
 //remove(trim) whitespaces
 string1 = [string1 stringByReplacingOccurrencesOfString:@" " withString:@""];

 NSString *string2 = @"Hello ";
 //remove(trim) whitespaces
 string2 = [string1 stringByReplacingOccurrencesOfString:@" " withString:@""]

 // compare strings without whitespaces
 if ([string1 isEuqalToString:string2]) {
 }

So if you want to use it directly -

if ([[yourString1 stringByReplacingOccurrencesOfString:@" " withString:@""] isEuqalToString:[yourString2 stringByReplacingOccurrencesOfString:@" " withString:@""]]) {
// Strings are compared without whitespaces.
}

Above will remove all whitespaces of your string, if you want to remove only leading and trailing whitespaces then there are a couple of post already available, you can create a category of string as mentioned in following stack overflow post - How to remove whitespace from right end of NSString?

@implementation NSString (TrimmingAdditions)

- (NSString *)stringByTrimmingLeadingCharactersInSet:(NSCharacterSet *)characterSet {
    NSUInteger location = 0;
    NSUInteger length = [self length];
    unichar charBuffer[length];    
    [self getCharacters:charBuffer];

    for (location; location < length; location++) {
        if (![characterSet characterIsMember:charBuffer[location]]) {
            break;
        }
    }

    return [self substringWithRange:NSMakeRange(location, length - location)];
}

- (NSString *)stringByTrimmingTrailingCharactersInSet:(NSCharacterSet *)characterSet {
    NSUInteger location = 0;
    NSUInteger length = [self length];
    unichar charBuffer[length];    
    [self getCharacters:charBuffer];

    for (length; length > 0; length--) {
        if (![characterSet characterIsMember:charBuffer[length - 1]]) {
            break;
        }
    }

    return [self substringWithRange:NSMakeRange(location, length - location)];
}

@end

Now once you have the methods available, you can call these on your strings to trim leading and trailing spaces like -

 // trim leading chars
 yourString1 = [yourString1 stringByTrimmingLeadingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
// trim trainling chars
yourString1 = [yourString1 stringByTrimmingTrailingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

// trim leading chars
 yourString2 = [yourString2 stringByTrimmingLeadingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
// trim trainling chars
yourString2 = [yourString2 stringByTrimmingTrailingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

// compare strings
if([yourString1 isEqualToString: yourString2]) {

}

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