ソフトウェアエンジニアの技術ブログ：Software engineer tech blog

open(my $in, "<", "test.dat") or die("could not open file.");

while(<$in>){
	$_ =~ s/abc/ABC/;
	print $_;
}

close($in);

vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
ABC
def
ghi
123
456

while(<$in>){
	$_ =~ s/abc/ABC/;
	if($_ =~ /[a-z]/){
		print $_;
	}	
}

なるほど、面白い
vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
def
ghi

サブルーチンをつくる。

sub max {
	my $max = $_[0];
	if ($_[1] > $max){
		$max = $_[1];
	}
	return $max;
}
print max(2, 8);

サブルーチンという名称ですが、要するに関数ですな。

sub max {
	my $max = shift(@_);
	foreach(@_){
		$max = $_ if $_ > $max;
	}
	return $max;
}
print max(2, 8, 100, 23, 38);

vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
100

なんかかなり駆け足できましたが、基礎はこれ位にしてdancerに入りましょう。

fileをopenします。

open(my $in, "<", "test.dat") or die("could not open file.");

while(<$in>){
	print $_;
}

close($in);

vagrant@vagrant-ubuntu-trusty-64:~/app$ cat test.dat
abc
def
ghi
123
456
789vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
abc
def
ghi
123
456
789

open(my $in, "<", "test.dat") or die("could not open file.");
open(my $out, ">", "test.out") or die("could not open file.");

while(<$in>){
	print $out $_;
}

close($in);
close($out);

vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
vagrant@vagrant-ubuntu-trusty-64:~/app$ cat test.out
abc
def
ghi
123
456
789

書き込みですな。

# ループ処理
my $i = 0;
while($i < 10){
	print "i = $i\n";
	$i++;
}
&#91;/perl&#93;

vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
i = 0
i = 1
i = 2
i = 3
i = 4
i = 5
i = 6
i = 7
i = 8
i = 9

for文
&#91;perl&#93;
for(my $i = 0; $i < 10; $i++){
	print "i = $i\n";
}
&#91;/perl&#93;

おおおおおお、foreachが可笑しなことになってる。。
&#91;perl&#93;
my @colors = qw(red green blue orange pink);

foreach my $color (@colors){
	print "color = $color\n";
}
&#91;/perl&#93;

vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
color = red
color = green
color = blue
color = orange
color = pink

ナニコレ?
&#91;perl&#93;
my @colors = qw(red green blue orange pink);

foreach (@colors){
	print "color = $_\n";
}
&#91;/perl&#93;

vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
color = red
color = green
color = blue
color = orange
color = pink

これは。。。
&#91;perl&#93;
my %sales = ("tanaka"=>150, "suzuki"=>300, "ohira"=>200);

foreach my $key (keys(%sales)){
		print "sales for $key in $sales{$key}\n"
}

vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
sales for tanaka in 150
sales for suzuki in 300
sales for ohira in 200

my $score = 75;

if ($score >= 80) {
	print("OK");
} elsif ($score >= 40) {
	print ("not ok...");
} else {
	print("take the test again")
}

1行で書く場合

my $score = 75;
print("OK!") if ($score >= 60);

my $a = 10;
my $b = 20;

my $max = $a > $b ? $a : $b;

my @sales = (300, 150, 200);
# @sales $#sale: 末尾の添字

print @sales[0..$#sales];

key and value

my %sales = ("tanaka"=>300, "suzuki"=>150, "ohira"=>200);

print $sales{"tanaka"};

条件分岐

my $score = 85;

if ($score >= 80) {
	print("ok!");
}

vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
ok!

my $score = 85;
my $name = "Luke";

if ($name eq "Luke") {
	print("I am your father!");
}

vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
I am your father!

ああああああ、何やってんだろう。

my $score = 85;
my $name = "Luke";

if (($name eq "Luke") &&($score >= 80)) {
	print("I am your father!");
}

my $x = 10;
my $y = 10.75;
my $z = 12_2425_241;

my $xx = 10 * 10;
my $yy = 10 % 3;
my $zz = 2 ** 3;

$x++;
$x--;

$x += 5;

my $a = "he\tllo"; # 特殊文字(\n, \t)が使える、変数展開がされる
my $b = 'he\tllo';

print $a;
print $b;

hellohellovagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
he llohe\tllo

こうも書ける。

my $name = "tom";
my $a = "hello, $name\n"; # 特殊文字(\n, \t)が使える、変数展開がされる
my $b = 'hello';

print $a;
print $b;

# . x 文字の連結

配列変数

my @sales = (150, 200, 300);
my @colors = ('red', 'green');
my @mixed = (150, 'red', 1.5);

print @sales;

my @inc = (1..100);

print @inc;

配列の読み出し

my @sales = (300, 150, 200);

print $sales[1];

my @sales = (300, 150, 200);

print @sales[0..2];

use strict;
use warnings;

print("hello world\n");

vagrant@vagrant-ubuntu-trusty-64:~/app$ perl hello.pl
hello world

my $msg;
$msg = "Hello World\n";

print $msg;

こうも書ける。

my $msg = "Studying Perl\n";
print $msg;