/// <summary>
/// Returns a part of a specified timestamp.
/// </summary>
/// <param name="format">Format definition for output.</param>
/// <param name="timestamp">Nuber of seconds since 1970 specifying a date.</param>
/// <returns>Part of the date, e.g. month or hours.</returns>
public static int idate(Context ctx, string format, int timestamp)
{
if (format == null || format.Length != 1)
{
//PhpException.InvalidArgument("format");
throw new ArgumentException();
}
return(GetDatePart(format[0], DateTimeUtils.UnixTimeStampToUtc(timestamp), PhpTimeZone.GetCurrentTimeZone(ctx)));
}