I was aware of this:

my $indent = ' 'x5;
# Yields '     '
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But didn't realize I could also do this:

my @list = (1)x5;
# Yields (1,1,1,1,1)
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So I can stop doing this:

  @placeholders = map {'?'} @columns;
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And start doing this:

  @placeholders = ('?')x @columns;
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