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<HTML><HEAD><TITLE>Recipe 2.18. Printing Correct Plurals (Perl Cookbook)</TITLE><METANAME="DC.title"CONTENT="Perl Cookbook"><METANAME="DC.creator"CONTENT="Tom Christiansen & Nathan Torkington"><METANAME="DC.publisher"CONTENT="O'Reilly & Associates, Inc."><METANAME="DC.date"CONTENT="1999-07-02T01:30:25Z"><METANAME="DC.type"CONTENT="Text.Monograph"><METANAME="DC.format"CONTENT="text/html"SCHEME="MIME"><METANAME="DC.source"CONTENT="1-56592-243-3"SCHEME="ISBN"><METANAME="DC.language"CONTENT="en-US"><METANAME="generator"CONTENT="Jade 1.1/O'Reilly DocBook 3.0 to HTML 4.0"><LINKREV="made"HREF="mailto:online-books@oreilly.com"TITLE="Online Books Comments"><LINKREL="up"HREF="ch02_01.htm"TITLE="2. Numbers"><LINKREL="prev"HREF="ch02_18.htm"TITLE="2.17. Putting Commas in Numbers"><LINKREL="next"HREF="ch02_20.htm"TITLE="2.19. Program: Calculating Prime Factors"></HEAD><BODYBGCOLOR="#FFFFFF"><img alt="Book Home" border="0" src="gifs/smbanner.gif" usemap="#banner-map" /><map name="banner-map"><area shape="rect" coords="1,-2,616,66" href="index.htm" alt="Perl Cookbook"><area shape="rect" coords="629,-11,726,25" href="jobjects/fsearch.htm" alt="Search this book" /></map><div class="navbar"><p><TABLEWIDTH="684"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="228"><ACLASS="sect1"HREF="ch02_18.htm"TITLE="2.17. Putting Commas in Numbers"><IMGSRC="../gifs/txtpreva.gif"ALT="Previous: 2.17. Putting Commas in Numbers"BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="228"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1"><ACLASS="chapter"REL="up"HREF="ch02_01.htm"TITLE="2. Numbers"></A></FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="228"><ACLASS="sect1"HREF="ch02_20.htm"TITLE="2.19. Program: Calculating Prime Factors"><IMGSRC="../gifs/txtnexta.gif"ALT="Next: 2.19. Program: Calculating Prime Factors"BORDER="0"></A></TD></TR></TABLE></DIV><DIVCLASS="sect1"><H2CLASS="sect1"><ACLASS="title"NAME="ch02-chap02_printing_0">2.18. Printing Correct Plurals</A></H2><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch02-pgfId-1349">Problem <ACLASS="indexterm"NAME="ch02-idx-1000008154-0"></A><ACLASS="indexterm"NAME="ch02-idx-1000008154-1"></A><ACLASS="indexterm"NAME="ch02-idx-1000008154-2"></A><ACLASS="indexterm"NAME="ch02-idx-1000008154-3"></A></A></H3><PCLASS="para">You're printing something like "<CODECLASS="literal">It</CODE> <CODECLASS="literal">took</CODE> <CODECLASS="literal">$time</CODE> <CODECLASS="literal">hours</CODE>", but "<CODECLASS="literal">It</CODE> <CODECLASS="literal">took</CODE> <CODECLASS="literal">1</CODE> <CODECLASS="literal">hours</CODE>" is ungrammatical. You would like to get it right.</P></DIV><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch02-pgfId-1355">Solution</A></H3><PCLASS="para">Use <CODECLASS="literal">printf</CODE> and a ternary conditional (<CODECLASS="literal">X</CODE> <CODECLASS="literal">?</CODE> <CODECLASS="literal">Y</CODE> <CODECLASS="literal">:</CODE> <CODECLASS="literal">Z</CODE>) to alter the noun or verb:</P><PRECLASS="programlisting">printf "It took %d hour%s\n", $time, $time == 1 ? "" : "s";printf "%d hour%s %s enough.\n", $time, $time == 1 ? "" : "s", $time == 1 ? "is" : "are";</PRE><PCLASS="para">Or, use the <ACLASS="indexterm"NAME="ch02-idx-1000008155-0"></A>Lingua::EN::Inflect module from CPAN as described in the Discussion.</P></DIV><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch02-pgfId-1373">Discussion</A></H3><PCLASS="para">The only reason inane messages like "<CODECLASS="literal">1</CODE> <CODECLASS="literal">file(s)</CODE> <CODECLASS="literal">updated</CODE>" appear is because their authors are too lazy to bother checking whether the count is 1 or not.</P><PCLASS="para">If your noun changes by more than an <CODECLASS="literal">"-s"</CODE>, you'll need to change the <CODECLASS="literal">printf</CODE> accordingly:</P><PRECLASS="programlisting">printf "It took %d centur%s", $time, $time == 1 ? "y" : "ies";</PRE><PCLASS="para">This is good for simple cases, but you'll get tired of writing it. This leads you to write funny functions like this:</P><PRECLASS="programlisting">sub noun_plural { local $_ = shift; # order really matters here! s/ss$/sses/ || s/([psc]h)$/${1}es/ || s/z$/zes/ || s/ff$/ffs/ || s/f$/ves/ || s/ey$/eys/ || s/y$/ies/ || s/ix$/ices/ || s/([sx])$/$1es/ || s/$/s/ || die "can't get here"; return $_;}*verb_singular = \&noun_plural; # make function alias</PRE><PCLASS="para">As you find more exceptions, your function will become increasingly convoluted. When you need to handle such morphological changes, turn to the flexible solution provided by the Lingua::EN::Inflect module from CPAN.</P><PRECLASS="programlisting">use Lingua::EN::Inflect qw(PL classical);classical(1); # why isn't this the default?while (<DATA>) { # each line in the data for (split) { # each word on the line print "One $_, two ", PL($_), ".\n"; }} # plus one more$_ = 'secretary general';print "One $_, two ", PL($_), ".\n";__END__fish fly ox species genus phylum cherub radius jockey index matrix mythosphenomenon formula </PRE><PCLASS="para">That produces the following:</P><PRECLASS="programlisting"><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One fish, two fish.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One fly, two flies.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One ox, two oxen.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One species, two species.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One genus, two genera.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One phylum, two phyla.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One cherub, two cherubim.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One radius, two radii.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One jockey, two jockeys.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One index, two indices.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One matrix, two matrices.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One mythos, two mythoi.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One phenomenon, two phenomena.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One formula, two formulae.</I></CODE></B></CODE><CODECLASS="userinput"><B><CODECLASS="replaceable"><I>One secretary general, two secretaries general.</I></CODE></B></CODE></PRE><PCLASS="para">This is one of the many things the module can do. It also handles inflections or conjugations for other parts of speech, provides number-insensitive comparison functions, figures out whether to use <ICLASS="firstterm">a</I> or <ICLASS="firstterm">an</I>, and plenty more.</P></DIV><DIVCLASS="sect2"><H3CLASS="sect2"><ACLASS="title"NAME="ch02-pgfId-1489">See Also</A></H3><PCLASS="para">The ternary ("hook-colon") operator discussed in <EMCLASS="emphasis">perlop </EM>(1) and in the <ACLASS="olink"HREF="../prog/ch02_05.htm#PERL2-CH-2-SECT-5.16">"Conditional Operator"</A> section of <ACLASS="olink"HREF="../prog/ch02_01.htm">Chapter 2</A> of <ACLASS="citetitle"HREF="../prog/index.htm"TITLE="Programming Perl"><CITECLASS="citetitle">Programming Perl</CITE></A>; the documentation with the CPAN module Lingua::EN::Inflect<ACLASS="indexterm"NAME="ch02-idx-1000008156-0"></A> <ACLASS="indexterm"NAME="ch02-idx-1000008158-0"></A><ACLASS="indexterm"NAME="ch02-idx-1000008158-1"></A><ACLASS="indexterm"NAME="ch02-idx-1000008158-2"></A><ACLASS="indexterm"NAME="ch02-idx-1000008158-3"></A></P></DIV></DIV><DIVCLASS="htmlnav"><P></P><HRALIGN="LEFT"WIDTH="684"TITLE="footer"><TABLEWIDTH="684"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="228"><ACLASS="sect1"HREF="ch02_18.htm"TITLE="2.17. 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