my @leute = qw(donald daisy mickey minnie clyde bonnie);

my @ungerade = grep $_ % 2 == 1, 0..$#leute;
my @gerade   = grep $_ % 2 == 0, 0..$#leute-1;

@leute[@ungerade, @gerade] = @leute[@gerade, @ungerade];

print "Ladies first: @leute";