string - 如何在 Perl 中重复一个字符串 N 次？

Question

在Python中，如果我这样做:

print "4" * 4

我明白了

> "4444"

在 Perl 中，我会得到

> 16

在 Perl 中是否有简单的方法来实现前者？

Answer 1

$ perl -e 'print "4" x 4; print "\n"'
4444

x 运算符记录在 perldoc perlop 中。顺便说一句，这里的二进制意味着一个带有两个参数的运算符，而不是由位组成。

Binary "x" is the repetition operator. In scalar context or if theleft operand is not enclosed in parentheses, it returns a string consistingof the left operand repeated the number of times specified by the rightoperand. In list context, if the left operand is enclosed in parenthesesor is a list formed by "qw/STRING/", it repeats the list. If the rightoperand is zero or negative, it returns an empty string or an emptylist, depending on the context.

       print '-' x 80;             # Print row of dashes

       print "\t" x ($tab/8), ' ' x ($tab%8);      # Tab over

       @ones = (1) x 80;           # A list of 80 1’s
       @ones = (5) x @ones;        # Set all elements to 5

perl -e 旨在从命令行执行 Perl 代码:

$ perl --helpUsage: perl [switches] [--] [programfile] [arguments]    -e program     one line of program (several -e's allowed, omit programfile)