Perl 数值变量
Perl 和我对于变量是否是数字存在分歧。我当然错了，但为什么呢？
my $bytes = 0;
# . . .
$bytes = $bytes + length($text);
# . . .
my $MB = $bytes / 1048576;
my $string = sprintf("Downloaded: %.1f MB\n", MB);
给出参数“MB”在 foo.pl 第 200 行的 sprintf 中不是数字。。
事实上，当我使用
my $string = "Downloaded: $MB MB\n";
它将字符串设置为 Downloaded: 3.09680080413818 MB 时可以看到，它是数字。
编辑：啊，愚蠢的错误，谢谢你发现它。
Perl and I disagree as to whether a variable is a number or not. I'm wrong, of course, but why?
my $bytes = 0;
# . . .
$bytes = $bytes + length($text);
# . . .
my $MB = $bytes / 1048576;
my $string = sprintf("Downloaded: %.1f MB\n", MB);
gives Argument "MB" isn't numeric in sprintf at foo.pl line 200..
It is, in fact, numeric as can be seen when I use
my $string = "Downloaded: $MB MB\n";
which sets the string to Downloaded: 3.09680080413818 MB.
Edit: Ah, silly mistake, thanks for catching it.
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评论（2）
您需要变量印记：
You need the variable sigil:
看起来你的意思可能是：
除此之外，这应该可行。
Looks like you probably meant:
other than that this should work.