"Logical pattern"lar haqida..

C# 9.0 dan boshlab, biz quyidagi 'logical pattern'ni yozish uchun not, and , va or pattern kombinatorlaridan foydalanamiz:

• Negated(inkor) not pattern :

if (input is not null)
{
    // ...
}

• Conjunctive and pattern - ikkala qolip ham ifodaga mos kelganda ishlatiladi:

Console.WriteLine(Classify(13));  // output: High
Console.WriteLine(Classify(-100));  // output: Too low
Console.WriteLine(Classify(5.7));  // output: Acceptable

static string Classify(double measurement) => measurement switch
{
    < -40.0 => "Too low",
    >= -40.0 and < 0 => "Low",
    >= 0 and < 10.0 => "Acceptable",
    >= 10.0 and < 20.0 => "High",
    >= 20.0 => "Too high",
    double.NaN => "Unknown",
};

Disjunctive or pattern - har qanday qolip ifodaga mos kelganda ishlatiladi:

Console.WriteLine(GetCalendarSeason(new DateTime(2021, 1, 19)));  // output: winter
Console.WriteLine(GetCalendarSeason(new DateTime(2021, 10, 9)));  // output: autumn
Console.WriteLine(GetCalendarSeason(new DateTime(2021, 5, 11)));  // output: spring

static string GetCalendarSeason(DateTime date) => date.Month switch
{
    3 or 4 or 5 => "spring",
    6 or 7 or 8 => "summer",
    9 or 10 or 11 => "autumn",
    12 or 1 or 2 => "winter",
    _ => throw new ArgumentOutOfRangeException(nameof(date), $"Date with unexpected month: {date.Month}."),
};

Yuqoridagi misoldan ko'rinib turibdiki, siz pattern kombinatorlarini pattern ichida qayta-qayta ishlatishingiz mumkin.