a `contains` on `List<String>` with `caseInsensitive: Boolean`?

# stdlib

[elect]

a contains on List<String> with caseInsensitive: Boolean?

[Chris Lee]

list.any { it.lowerCase() == value }

[elect]

I know, but this is the stdlib

[Chris Lee]

wouldn’t expect a fairly limited use-case method such as “contains case insensitive” to be in stdlib. All kinds of permutations - contains matching regex, contains prefix, and so forth. All readily doable with minimal code today.

[ephemient]

we should not be adding new case sensitivity APIs that don't take locale into consideration
Locale is currently JVM-only
thus, not a great fit for stdlib currently IMO

[ephemient]

also if this is something you're repeating, it would be better to use contains on a (case-folded) Set<String>

[CLOVIS]

list.any { it.equals(value, ignoreCase = true) }
is probably faster / uses less memory

[Klitos Kyriacou]

Not only faster, but probably more correct (for certain non-English characters)

[ephemient]

equals(ignoreCase = true) does not handle some non-English characters well (most notably Turkic languages)

[ephemient]

for example,

import java.text.Collator
import java.util.Locale

Collator.getInstance(Locale("tr")).apply { strength = Collator.SECONDARY }.compare("I", "i") // -1, because these are not case-insensitive equal in Turkish
Collator.getInstance(Locale("tr")).apply { strength = Collator.SECONDARY }.compare("İ", "i") // 0, because these are case-insensitive equal in Turkish
Collator.getInstance(Locale("de")).apply { strength = Collator.SECONDARY }.compare("SS", "ß") // 0, because these are case-insensitive equal in German

equals(ignoreCase = true) has no way to get any of these cases right. you should really consider it as an ASCII-only API

[elect]

ok, got it

[ephemient]

if you are doing it repeatedly, you can pre-compute Collator.getCollationKey, which will be more efficient than doing case-insensitive comparisons repeatedly. for example,

val collationKeys = buildSet { listOfStrings.mapTo(this) { collator.getCollationKey(it) } }

collator.getCollationKey(string1) in collationKeys
collator.getCollationKey(string2) in collationKeys
// etc.

[elect]

No, I just had to do it a couple of time in a short amount of time