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统计宏字符串输出内容中某个字符出现的次数

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统计宏字符串输出内容中某个字符出现的次数

如何概括这宏使其打印字符串出现的次数并允许任意分隔符（包括空格）？谢谢。

输出结果可能是：

如果为 FALSE，则为 0；如果为 TRUE，则为 1,2,3... 发生的次数。

\documentclass{article}
\usepackage{xparse}

\ExplSyntaxOn
\NewDocumentCommand{\ifmember}{mmmm}
 {
  \clist_if_in:onTF { #2 } { #1 } { #3 } { #4 }
 }
\cs_generate_variant:Nn \clist_if_in:nnTF { o }
\ExplSyntaxOff

\begin{document}

\ifmember{3}{3,4}{True}{False} (expected: True)

\ifmember{3}{ 3 ,4}{True}{False} (expected: True)

\newcommand{\foo}{3,4}
\ifmember{3}{\foo}{True}{False} (expected: True)

\renewcommand{\foo}{3, 4}

\ifmember{4}{\foo}{True}{False} (expected: True)

\ifmember{foo}{\foo}{True}{False} (expected: False)

\end{document}

答案1

您可以映射列表并根据给定的标记列表检查每个项目，如果匹配则增加计数器。最后，打印计数器的值。

分隔符（默认为逗号）在可选参数中指定。

\documentclass{article}
%\usepackage{xparse} % no longer needed

\ExplSyntaxOn

\NewDocumentCommand{\countmember}{O{,}mm}
 {
  \krantz_countmember:onn { #3 } { #2 } { #1 }
 }

\seq_new:N \l__krantz_countmember_items_seq
\int_new:N \l__krantz_countmember_count_int

\cs_new_protected:Nn \krantz_countmember:nnn
 {
  \int_zero:N \l__krantz_countmember_count_int
  \seq_set_split:Nnn \l__krantz_countmember_items_seq { #3 } { #1 }
  \seq_map_inline:Nn \l__krantz_countmember_items_seq
   {
    \tl_if_eq:nnT { ##1 } { #2 } { \int_incr:N \l__krantz_countmember_count_int }
   }
  \int_to_arabic:n { \l__krantz_countmember_count_int }
 }
\cs_generate_variant:Nn \krantz_countmember:nnn { o }

\ExplSyntaxOff

\begin{document}

\countmember{3}{3,4} (expected: 1)

\countmember{3}{ 3 ,4} (expected: 1)

\newcommand{\foo}{3,4}
\countmember{3}{\foo} (expected: 1)

\renewcommand{\foo}{3, 4, 4}

\countmember{4}{\foo} (expected: 2)

\countmember{foo}{\foo} (expected: 0)

\countmember[\\]{1}{1 \\ 2 \\ 1 \\ 0} (expected: 2)

\countmember[ ]{2}{1 2 1 0} (expected: 1)

\renewcommand{\foo}{1 2 1 0}

\countmember[ ]{2}{\foo} (expected: 1)

\end{document}

在此处输入图片描述

可以添加一个尾随可选参数，该参数应该是一个控制序列，结果将存储在其中以供以后使用。

\documentclass{article}
%\usepackage{xparse} % no longer needed

\ExplSyntaxOn

\NewDocumentCommand{\countmember}{O{,}mmo}
 {
  \krantz_countmember:onn { #3 } { #2 } { #1 }
  \IfNoValueTF { #4 }
   {% just print the count
    \int_to_arabic:n { \l__krantz_countmember_count_int }
   }
   {% store
    \tl_clear_new:N #4
    \tl_set:Nx #4 { \int_to_arabic:n { \l__krantz_countmember_count_int } }
   }
 }

\seq_new:N \l__krantz_countmember_items_seq
\int_new:N \l__krantz_countmember_count_int

\cs_new_protected:Nn \krantz_countmember:nnn
 {
  \int_zero:N \l__krantz_countmember_count_int
  \seq_set_split:Nnn \l__krantz_countmember_items_seq { #3 } { #1 }
  \seq_map_inline:Nn \l__krantz_countmember_items_seq
   {
    \tl_if_eq:nnT { ##1 } { #2 } { \int_incr:N \l__krantz_countmember_count_int }
   }
 }
\cs_generate_variant:Nn \krantz_countmember:nnn { o }

\ExplSyntaxOff

\begin{document}

\countmember{3}{3,4} (expected: 1)

\countmember{3}{ 3 ,4} (expected: 1)

\newcommand{\foo}{3,4}
\countmember{3}{\foo} (expected: 1)

\renewcommand{\foo}{3, 4, 4}

\countmember{4}{\foo} (expected: 2)

\countmember{foo}{\foo} (expected: 0)

\countmember[\\]{1}{1 \\ 2 \\ 1 \\ 0} (expected: 2)

\countmember[ ]{2}{1 2 1 0} (expected: 1)

\renewcommand{\foo}{1 2 1 0}

\countmember[ ]{2}{\foo} (expected: 1)

% store in \foo

\countmember{1}{1,2,2,1,1,2}[\foo]

\foo

\end{document}

输出与之前相同，但您还会在最后看到“3”。

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