将字符串变量附加到 Perl 中的固定字符串

问题描述

我有一个在提示下输入的变量:

I have a variable that is entered at a prompt:

my $name = <>;

我想将一个固定的字符串 '_one' 附加到它(在一个单独的变量中).

I want to append a fixed string '_one'to this (in a separate variable).

例如如果 $name = Smith 那么它就变成 'Smith_one'

E.g. if $name = Smith then it becomes 'Smith_one'

我尝试了几种方法都没有得到正确的结果，例如:

I have tried several various ways which do not give me the right results, such as:

my $one = "${name}_one";

^ _one 当我打印出来时出现在下一行，当我使用它时，根本不包括_one.

^ The _one appears on the next line when I print it out and when I use it, the _one is not included at all.

还有:

my $one = $name."_one";

^ '_one' 出现在字符串的开头.

^ The '_one' appears at the beginning of the string.

还有:

my $end = '_one';
my $one = $name.$end;
or
my $one = "$name$end";

这些都没有产生我想要的结果，所以我必须遗漏一些与提示中输入的格式有关的东西，也许.想法赞赏！

None of these produce the result I want, so I must be missing something related to how the input is formatted from the prompt, perhaps. Ideas appreciated!

推荐答案

您的问题与字符串追加无关:当您读取一行时(例如通过 )，然后记录输入分隔符包含在那个字符串中；这通常是一个换行符 \n.要删除换行符，chomp 变量:

Your problem is unrelated to string appending: When you read a line (e.g. via <>), then the record input separator is included in that string; this is usually a newline \n. To remove the newline, chomp the variable:

    my $name = <STDIN>; # better use explicit filehandle unless you know what you are doing
    # now $name eq "Smith\n"
    chomp $name;
    # now $name eq "Smith"

要将变量插入到字符串中，通常不需要使用的 ${name} 语法.这些行都会将 _one 附加到您的字符串并创建一个新字符串:

To interpolate a variable into a string, you usually don't need the ${name} syntax you used. These lines will all append _one to your string and create a new string:

    "${name}_one"  # what you used
    "$name\_one"   # _ must be escaped, else the variable $name_one would be interpolated
    $name . "_one"
    sprintf "%s_one", $name
    # etc.

这会将 _one 附加到您的字符串中，并仍将其存储在 $name 中:

And this will append _one to your string and still store it in $name:

    $name .= "_one"

这篇关于将字符串变量附加到 Perl 中的固定字符串的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！