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def handle_error(index):
    if index == 0:
        for index, it in enumerate(iterators):
            try:
                next(it)
                break
            except StopIteration:
                pass
        else:
            return
        compares = "longer"
    else:
        compares = "shorter"
    end_index = "" if index == 1 else f"-{index}"
    raise ValueError(f"zip() argument {index + 1} is {compares} than arguments 1{end_index}")


def zip_it(*iterables, strict=False):
    iterators = [iter(it) for it in iterables]
    if iterators:
        while True:
            try:
                zipped = []
                for it in iterators:
                    zipped.append(next(it))
            except StopIteration:
                if strict:
                    handle_error(iterators, len(zipped))
                break
            else:
                yield tuple(zipped)

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def count_exhausted(iterators):
    exhausted = []
    for it in iterators:
        try:
            next(it)
        except StopIteration:
            exhausted.append(it)
    return len(exhausted)

def build_exception(relation, position):
    maybe_plural = "s 1-" if position > 2 else " "
    return ValueError(
        f"zip_it() argument {position} is {relation} than "
        f"argument{maybe_plural}{position - 1}"
    )

def zip_it(*iterables, strict=False):
    if not iterables:
        return
    iterators = [iter(it) for it in iterables]
    while True:
        zipped = tuple(map(next, iterators))
        if len(zipped) < len(iterators):
            if not strict:
                break
            if zipped:
                raise build_exception("shorter", len(zipped) + 1)
            num_exhausted = count_exhausted(iterators)
            if num_exhausted == len(iterators):
                break
            raise build_exception("longer", num_exhausted + 1)
        yield zipped

Code: Alles auswählen

TYPE
  TStr  = String[7];
  TDay  = (Mon,Tue,Wed,Thu,Fri,Sat,Sun);
  TDays = SET OF TDay;

CONST
  DayNames: ARRAY[0..6] OF String[2] = ('Mo','Di','Mi','Do','Fr','Sa','So');

VAR
  d: TDay;  a, b: TDays;


PROCEDURE PrintDays(t: TStr; days: TDays);
VAR
  d: TDay;  p: ^Byte;  i, m: Byte;
BEGIN
  FOR i := 1 TO 5 - Length(t) DO Write(' ');
  Write(t, ' = ');
  p := Addr(days);  i := p^;  m := 128;
  WHILE m <> 0 DO
    BEGIN
      IF i AND m = 0 THEN Write('0') ELSE Write('1');
      m := m SHR 1;
    END;
  Write(' = ', i:3, ' = ');
  FOR d := Mon TO Sun DO IF d IN days THEN Write(DayNames[Ord(d)], ' ');
  WriteLn;
END;

BEGIN
  WriteLn('Menge von Tagen wird in ', SizeOf(TDays), ' Byte(s) gespeichert.');
  FOR d := Mon TO Sun DO PrintDays(DayNames[Ord(d)], [d]);
  PrintDays('all', [Mon..Sun]);
  a := [Mon, Sat, Sun];  b := [Wed, Sat];
  PrintDays('a', a);
  PrintDays('b', b);
  PrintDays('a + b', a + b);
  PrintDays('a * b', a * b);
  PrintDays('a - b', a - b);
END.

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Menge von Tagen wird in 1 Byte(s) gespeichert.
   Mo = 00000001 =   1 = Mo
   Di = 00000010 =   2 = Di
   Mi = 00000100 =   4 = Mi
   Do = 00001000 =   8 = Do
   Fr = 00010000 =  16 = Fr
   Sa = 00100000 =  32 = Sa
   So = 01000000 =  64 = So
  all = 01111111 = 127 = Mo Di Mi Do Fr Sa So
    a = 01100001 =  97 = Mo Sa So
    b = 00100100 =  36 = Mi Sa
a + b = 01100101 = 101 = Mo Mi Sa So
a * b = 00100000 =  32 = Sa
a - b = 01000001 =  65 = Mo So

Code: Alles auswählen

Menge von Tagen wird in 4 Byte(s) gespeichert.