「3-3-2.複数のファイルをまとめて、1つのファイルにする」とは逆に1つの入力ファイルから複数の出力ファイルに振り分ける方法について解説します。ここでは、日本郵政公社が提供している郵便番号データを都道府県別に出力する方法を例にとって説明します。郵便番号データは下記のサイトにあるので参照してください。
http://www.post.japanpost.jp/zipcode/
入力データの1項目目はJISで定められた都道府県コード（2バイト）と市区町村コード（3バイト）の2つを組み合わせた5バイトのデータになっています。そこで、入力データの1項目目から先頭2バイトを取り、そのデータに基づいて、出力ファイルを分けて出力します。
具体的には、【スクリプト】その１を見ていただければわかるように、Perlでは、open命令およびclose命令ともに引数に変数を指定することができます。「open($w_out,"$w_file");」や「close($w_out);」のような形式になりますが、入力データの1つとして、県別の出力ファイル名を指定したファイルをあらかじめ用意しておくことで、スクリプト自体がすっきりとした形になります。open命令やclose命令を定数で指定した場合、どのようになるかを【スクリプト】その２で提示していますので、比較すると、どのくらい簡潔になるかがわかるでしょう。入出力ファイルが増えてきた場合、このように変数で指定することでスクリプトがすっきりと表示できるようになります。
01101,"060 ","0600000","ホッカイドウ","サッポロシチュウオウク","イカニケイサイガナイバアイ","北海道","札幌市中央区","以下に掲載がない場合",0,0,0,0,0,0
01101,"064 ","0640941","ホッカイドウ","サッポロシチュウオウク","アサヒガオカ","北海道","札幌市中央区","旭ケ丘",0,0,1,0,0,0
01,01HOKKAIDO.CSV
02,02AOMORI.CSV
03,03IWATE.CSV
04,04MIYAGI.CSV
05,05AKITA.CSV
06,06YAMAGATA.CSV
07,07FUKUSHIMA.CSV
08,08IBARAKI.CSV
09,09TOCHIGI.CSV
10,10GUMMA.CSV
11,11SAITAMA.CSV
12,12CHIBA.CSV
13,13TOKYO.CSV
14,14KANAGAWA.CSV
15,15NIIGATA.CSV
16,16TOYAMA.CSV
17,17ISHIKAWA.CSV
18,18FUKUI.CSV
19,19YAMANASHI.CSV
20,20NAGANO.CSV
21,21GIFU.CSV
22,22SHIZUOKA.CSV
23,23AICHI.CSV
24,24MIE.CSV
25,25SHIGA.CSV
26,26KYOTO.CSV
27,27OSAKA.CSV
28,28HYOGO.CSV
29,29NARA.CSV
30,30WAKAYAMA.CSV
31,31TOTTORI.CSV
32,32SHIMANE.CSV
33,33OKAYAMA.CSV
34,34HIROSHIMA.CSV
35,35YAMAGUCHI.CSV
36,36TOKUSHIMA.CSV
37,37KAGAWA.CSV
38,38EHIME.CSV
39,39KOCHI.CSV
40,40FUKUOKA.CSV
41,41SAGA.CSV
42,42NAGASAKI.CSV
43,43KUMAMOTO.CSV
44,44OITA.CSV
45,45MIYAZAKI.CSV
46,46KAGOSHIMA.CSV
47,47OKINAWA.CSV
# ken1.pl
# 内容 : 郵便番号データを県別に分割するスクリプト
# Copyright (c) 2002 Mitsuo Minagawa, All rights reserved.
# (minagawa@fb3.so-net.ne.jp)
# 使用方法 : c:\>perl ken1.pl
#
open(IN1,"ken_all.csv");
open(IN2,"ken.txt");
while ($line1 = <IN2>) {
chomp($line1);
@in2 = split(",",$line1,-1);
$w_out = OUT.$in2[0];
$w_file = ">".$in2[1];
open($w_out,"$w_file");
}
while ($line1 = <IN1>) {
chomp($line1);
# CSV形式の $line1 から値を取り出して @in1 に入れる
my $temp = $line1;
$temp =~ s/(?:\x0D\x0A|[\x0D\x0A])?$/,/;
@in1 = map {/^"(.*)"$/ ? scalar($_ = $1, s/""/"/g, $_) : $_}
($temp =~ /("[^"]*(?:""[^"]*)*"|[^,]*),/g);
$w_ken = substr($in1[0],0,2);
$w_out = "OUT".$w_ken;
print $w_out "$line1\n";
}
close(IN1);
while ($line1 = <IN2>) {
chomp($line1);
@in2 = split(",",$line1,-1);
$w_out = OUT.$in2[0];
close($w_out);
}
close(IN2);
# ken2.pl
# 内容 : 郵便番号データを県別に分割するスクリプト
# Copyright (c) 2002 Mitsuo Minagawa, All rights reserved.
# (minagawa@fb3.so-net.ne.jp)
# 使用方法 : c:\>perl ken2.pl
#
open(IN1,"ken_all.csv");
open(OUT01,">01HOKKAIDO.CSV");
open(OUT02,">02AOMORI.CSV");
open(OUT03,">03IWATE.CSV");
open(OUT04,">04MIYAGI.CSV");
open(OUT05,">05AKITA.CSV");
open(OUT06,">06YAMAGATA.CSV");
open(OUT07,">07FUKUSHIMA.CSV");
open(OUT08,">08IBARAKI.CSV");
open(OUT09,">09TOCHIGI.CSV");
open(OUT10,">10GUMMA.CSV");
open(OUT11,">11SAITAMA.CSV");
open(OUT12,">12CHIBA.CSV");
open(OUT13,">13TOKYO.CSV");
open(OUT14,">14KANAGAWA.CSV");
open(OUT15,">15NIIGATA.CSV");
open(OUT16,">16TOYAMA.CSV");
open(OUT17,">17ISHIKAWA.CSV");
open(OUT18,">18FUKUI.CSV");
open(OUT19,">19YAMANASHI.CSV");
open(OUT20,">20NAGANO.CSV");
open(OUT21,">21GIFU.CSV");
open(OUT22,">22SHIZUOKA.CSV");
open(OUT23,">23AICHI.CSV");
open(OUT24,">24MIE.CSV");
open(OUT25,">25SHIGA.CSV");
open(OUT26,">26KYOTO.CSV");
open(OUT27,">27OSAKA.CSV");
open(OUT28,">28HYOGO.CSV");
open(OUT29,">29NARA.CSV");
open(OUT30,">30WAKAYAMA.CSV");
open(OUT31,">31TOTTORI.CSV");
open(OUT32,">32SHIMANE.CSV");
open(OUT33,">33OKAYAMA.CSV");
open(OUT34,">34HIROSHIMA.CSV");
open(OUT35,">35YAMAGUCHI.CSV");
open(OUT36,">36TOKUSHIMA.CSV");
open(OUT37,">37KAGAWA.CSV");
open(OUT38,">38EHIME.CSV");
open(OUT39,">39KOCHI.CSV");
open(OUT40,">40FUKUOKA.CSV");
open(OUT41,">41SAGA.CSV");
open(OUT42,">42NAGASAKI.CSV");
open(OUT43,">43KUMAMOTO.CSV");
open(OUT44,">44OITA.CSV");
open(OUT45,">45MIYAZAKI.CSV");
open(OUT46,">46KAGOSHIMA.CSV");
open(OUT47,">47OKINAWA.CSV");
while ($line1 = <IN1>) {
chomp($line1);
# CSV形式の $line1 から値を取り出して @in1 に入れる
my $temp = $line1;
$temp =~ s/(?:\x0D\x0A|[\x0D\x0A])?$/,/;
@in1 = map {/^"(.*)"$/ ? scalar($_ = $1, s/""/"/g, $_) : $_}
($temp =~ /("[^"]*(?:""[^"]*)*"|[^,]*),/g);
$w_ken = substr($in1[0],0,2);
$w_out = "OUT".$w_ken;
print $w_out "$line1\n";
}
close(IN1);
close(OUT01);
close(OUT02);
close(OUT03);
close(OUT04);
close(OUT05);
close(OUT06);
close(OUT07);
close(OUT08);
close(OUT09);
close(OUT10);
close(OUT11);
close(OUT12);
close(OUT13);
close(OUT14);
close(OUT15);
close(OUT16);
close(OUT17);
close(OUT18);
close(OUT19);
close(OUT20);
close(OUT21);
close(OUT22);
close(OUT23);
close(OUT24);
close(OUT25);
close(OUT26);
close(OUT27);
close(OUT28);
close(OUT29);
close(OUT30);
close(OUT31);
close(OUT32);
close(OUT33);
close(OUT34);
close(OUT35);
close(OUT36);
close(OUT37);
close(OUT38);
close(OUT39);
close(OUT40);
close(OUT41);
close(OUT42);
close(OUT43);
close(OUT44);
close(OUT45);
close(OUT46);
close(OUT47);
入力データ(県別の出力ファイル名)のサンプルはこちらにあります。