如何在Perl中获取字符串的长度？

Question

什么是Perl相当于strlen()？

Answer 1

perldoc -f length

   length EXPR
   length  Returns the length in characters of the value of EXPR.  If EXPR is
           omitted, returns length of $_.  Note that this cannot be used on an
           entire array or hash to find out how many elements these have.  For
           that, use "scalar @array" and "scalar keys %hash" respectively.

           Note the characters: if the EXPR is in Unicode, you will get the num-
           ber of characters, not the number of bytes.  To get the length in
           bytes, use "do { use bytes; length(EXPR) }", see bytes.

Answer 2

虽然'length()'是应该在任何合理的代码中使用的正确答案,但是应该提到阿比盖尔的长度恐怖,如果只是为了Perl传说.

基本上,技巧包括使用catch-all音译操作符的返回值:

print "foo" =~ y===c;   # prints 3

y /// c用自己替换所有字符(由于补码选项'c'),并返回替换的字符数(因此,有效地,字符串的长度).

Answer 3

length($string)