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如何获取字符串中字符出现的次数

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如何获取字符串中字符出现的次数

如何获取字符串中字符出现的次数？

\documentclass[14pt]{extarticle}
\usepackage{xstring}
\usepackage{forloop}
\usepackage{ifthen}
\usepackage{pgfkeys}
\newcommand{\fios}{hellow world}
\begin{document}
%\StrCount{\fios}{e}
%\StrChar{\fios}{1}
\StrLen{\fios}[\varL]
\varL

\vspace{5ex}
\newcounter{loop}
\forloop{loop}{1}{\value{loop}< \varL}
{\StrChar{\fios}{\arabic{loop}}~--
\par
}
\end{document}

我需要得到：

h - 1
e - 1
l - 3
o - 2
w - 2
r - 1
d - 1

答案1

这是 Lua 代码片段，字符串中有一些 CJKV 字符。我从 TeX Live 中选择了一种 opentype 字体，但它不包含一些变音字母（例如 č、ř 和 š），希望它足以作为处理 UTF-8 字符串的演示。我们运行lualatex mal-letters.tex。

% lualatex mal-letters.tex
\documentclass[a4paper]{article}
\pagestyle{empty}
\parindent=0pt
\usepackage{luacode} % to be able to write Lua code
\usepackage{fontspec} % to be able to load fonts (CJKV)

\begin{document}
\begin{luacode*}
chars={} -- Lua table to store occurencies
function countme() -- the core function
text=tex.toks[0] -- pass an argument from TeX
unicode.utf8.gsub(text, ".", function(s) -- find any utf8 char
   if not chars[s] then chars[s]=0 end -- define it if it is not
   chars[s]=chars[s]+1 -- plus one as a char has been found
   return s -- don't change an original string
   end) -- end of function and gsub
-- print the results to the terminal
for letter,count in pairs(chars) do
   print(letter, count)
   -- comment out the following line, if you don't have that font (texmf-dist/fonts/opentype/public/fandol/fandolsong-regular.otf) and check out the terminal
   tex.print("{\\setmainfont{FandolSong}"..letter.."} ("..count..");")
   end   
end -- function, countme
\end{luacode*}
\def\occurs#1{\toks0{#1}\directlua{countme()}}
% This particular font doesn't contain č, ř, š etc., but it does contain CJKV.
\occurs{你怎么样? Pavel Stříž, číšník. さよなら。}
\end{document}

使用 CJKV 字符的示例

在终端中，我们会发现与此类似的结构：

ž   1
?   1
你   1
么   1
。   1
な   1
,   1
怎   1
a   1
さ   1
.   1
k   1
样   1
ら   1
P   1
š   1
n   1
č   1
l   1
ř   1
よ   1
    4
í   3
e   1
v   1
S   1
t   1

答案2

使用 xstring 进行编程很容易（没有无用的测试）：

\documentclass{extarticle}
\usepackage{xstring}
\newcommand\fios{hellow world}
\newcommand\occurs[1]{%
    \ifhmode\par\fi\begingroup\expandarg
    \StrDel{#1}{ }[\tempstr]%
    \occuraux\endgroup
}
\newcommand\occuraux{%
    \unless\ifx\tempstr\empty
        \StrSplit\tempstr1\currentchar\remainstr
        \currentchar\space-- \StrCount\tempstr\currentchar\par
        \let\tempstr\remainstr
        \StrDel\tempstr\currentchar[\tempstr]%
        \expandafter\occuraux
    \fi
}
\begin{document}
\occurs{hello world}
\bigskip

\occurs\fios
\end{document}

在此处输入图片描述

答案3

使用expl3和l3regex：

\documentclass{article}
\usepackage{xparse,l3regex}

\ExplSyntaxOn
\NewDocumentCommand{\countchar}{mm}
 {% #1 = character, #2 = string
  \youra_count_char:nn { #1 } { #2 }
  \int_to_arabic:n { \l_youra_count_char_int }
 }

\NewDocumentCommand{\countallchars}{m}
 {% #1 = string
  \youra_count_all_chars:n { #1 }
 }

\int_new:N \l_youra_count_char_int
\seq_new:N \l_youra_count_chars_seq

\cs_new_protected:Npn \youra_count_char:nn #1 #2
 {
  \regex_count:nnN { #1 } { #2 } \l_youra_count_char_int
 }

\cs_new_protected:Npn \youra_count_all_chars:n #1
 {
  \seq_set_split:Nnn \l_youra_count_chars_seq { } { #1 }
  \seq_remove_duplicates:N \l_youra_count_chars_seq
  \seq_remove_all:Nn \l_youra_count_chars_seq { ~ }
  \seq_map_inline:Nn \l_youra_count_chars_seq
   {
    \par
    \youra_count_char:nn { ##1 } { #1 }
    ##1 ~ - ~ \int_to_arabic:n { \l_youra_count_char_int }
    \par
   }
 }

\ExplSyntaxOff

\begin{document}

\countchar{h}{hello world}

\countallchars{hello world}

\end{document}

在此处输入图片描述

单字符版本仅使用\regex_count:nnN并传递获得的结果；完整版本将字符串按序列拆分，删除重复项和可能的空格，然后映射序列以对每个项目进行计数。

答案4

这里，使用stringstrings包，我提供了两个版本：一个按字母顺序计数（\countstring），另一个按出现顺序计数（\Countstring）。

\documentclass{article}
\usepackage{stringstrings}
\def\countstring#1{%
  \caselower[q]{#1}%
  \testchar{\thestring}{a}\testchar{\thestring}{b}\testchar{\thestring}{c}%
  \testchar{\thestring}{d}\testchar{\thestring}{e}\testchar{\thestring}{f}%
  \testchar{\thestring}{g}\testchar{\thestring}{h}\testchar{\thestring}{i}%
  \testchar{\thestring}{j}\testchar{\thestring}{k}\testchar{\thestring}{l}%
  \testchar{\thestring}{m}\testchar{\thestring}{n}\testchar{\thestring}{o}%
  \testchar{\thestring}{p}\testchar{\thestring}{q}\testchar{\thestring}{r}%
  \testchar{\thestring}{s}\testchar{\thestring}{t}\testchar{\thestring}{u}%
  \testchar{\thestring}{v}\testchar{\thestring}{w}\testchar{\thestring}{x}%
  \testchar{\thestring}{y}\testchar{\thestring}{z}%
}
\def\testchar#1#2{%
  \findchars[q]{#1}{#2}\ifnum\theresult>0\par\noindent#2 - \theresult\par\fi}
\def\Countstring#1{\caselower[q]{#1}\expandafter\Countstringhelp\thestring\relax}
\def\Countstringhelp#1#2\relax{%
  \ifcsname #1Chars\endcsname\else%
    \testchar{\thestring}{#1}%
    \ifnum\theresult>0\relax\expandafter\def\csname #1Chars\endcsname{\theresult}\fi%
  \fi
  \ifx\relax#2\else\Countstringhelp#2\relax\fi%
}
\begin{document}
\countstring{Hellow World}
\noindent\hrulefill
\Countstring{Hellow World}
\end{document}

在此处输入图片描述

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