[FIXED] Get one letter abbreviation of week day of a date in java

Issue

As far I know, in Java I can get weekdays in normal (Friday) or short mode (Fri). But, there is any way to obtain only first letter?

I thought I can get first letter using "substring", but it won't be correct for all languages. For example, spanish weekdays are: Lunes, Martes, Miércoles, Jueves, Viernes, Sábado and Domingo, and first letter for "Miércoles" is X instead of M to difference it from "Martes".

Solution

In Android you can use SimpleDateFormat with "EEEEE". In the next example you can see it.

SimpleDateFormat formatLetterDay = new SimpleDateFormat("EEEEE",Locale.getDefault());
String letter = formatLetterDay.format(new Date());

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EDIT: it's actually not entirely true. The result on Android could have more than a single letter (and also non-unique, if this matters), but this is what we have. Here's proof that you won't get these characteristics on Android, going over all locales. It's written in Kotlin, but should work for Java too, of course:

val charCountStats = SparseIntArray()
Locale.getAvailableLocales().forEach { locale ->
    val sb = StringBuilder("$locale : ")
    val formatLetterDay = SimpleDateFormat("EEEEE", locale)
    for (day in 1..7) {
        val cal = Calendar.getInstance()
        cal.set(Calendar.DAY_OF_WEEK, day)
        val letter: String = formatLetterDay.format(cal.time)
        charCountStats.put(letter.length, charCountStats.get(letter.length, 0)+1)
        sb.append(letter)
        if (day != 7)
            sb.append(',')
    }
    Log.d("AppLog", "$sb")
}
Log.d("AppLog", "stats:")
charCountStats.forEach { key, value ->
    Log.d("AppLog", "formatted days with $key characters:$value")
}

And the result is that for most cases it's indeed a single letter, but for many it's more, and can even reaches 8 characters (though it might look as less letters, even one) :

formatted days with 1 characters:4889
formatted days with 2 characters:471
formatted days with 3 characters:99
formatted days with 4 characters:58
formatted days with 5 characters:3
formatted days with 8 characters:3

Example of a locale that it shows as 3 letters (and not just has 3 letters) is "wo" ("Wolof" language), as this is the result for each of its days of the week using the above formatting:

Dib,Alt,Tal,Àla,Alx,Àjj,Ase

Answered By - Husky
Answer Checked By - Willingham (JavaFixing Volunteer)