Question

我正在尝试从字符串

中删除两个字符

This is what you have

使用

substr ($string, 5, 2) = "";

这两个字符被删除，但留下了一个额外的空格。我获得了

This  what you have

但我希望得到

This what you have

任何人都可以帮助我摆脱那个空间吗？

Answer 1

如果您尝试从is删除单词This is what you have及其旁边的空格之一，则您需要删除3个字符而不是仅删除2个字符。 / p>

Answer 2

字符串与数组一样，从位置0开始：

say '012345679';
my $str = "This is what you have";
say $str;

--output:--
012345679
This is what you have

要删除'is'和'is'之前的空格，您需要删除位置4,5,6：

012345679
This is what you have
    ^^^
    |||

......你可以这样做：

say '012345679';
my $str = "This is what you have";
say $str;

substr($str, 4, 3) = "";
say $str;

--output:--
012345679
This is what you have
This what you have

或者，您可以通过删除位置5,6,7来删除'is'和'is'之后的空格：

012345679
This is what you have
     ^^^
     |||

...像这样：

say '012345679';
my $str = "This is what you have";
say $str;

substr($str, 5, 3) = "";
say $str;

--output:--
012345679
This is what you have
This what you have

但是，在perl中，大多数人使用s///（替换运算符）进行替换：

s/find me/replace with me/

所以，你可以这样做：

my $str = "This is what you have"; 
say $str;

$str =~ s/\bis\b //;  # \b means 'word boundary'
say $str;

--output:--
012345679
This is what you have
This what you have

perl程序员很懒，计算职位太难了。你做需要知道大多数情况下的正则表达式。

如果要删除字符串中出现的所有'is'，则可以添加'g'（全局）标记：

my $str = "This is what you have, but his hat is black isn't it?";
say $str;

$str =~ s/\bis\b //g;
say $str;

--output:--
This is what you have, but his hat is black isn't it?
This what you have, but his hat black isn't it?
  ^                      ^            ^
  |                      |            |
    skips 'is' embedded in other words

Answer 3

我不认为您可以为substr命令的结果分配一个字符串，就像您尝试的那样，并获得预期的结果。请尝试这种方式：

$ newstring = substr（$ string，0,4）。 SUBSTR（$字符串，5）;

使用perl中的substr删除字符

3 个答案: