[转 - 改] Perl初级教程 （二）

【对于字符串】

$b = 'BB';
$c = 'CC';
$a = 'AA';

?

$a = $b . $c; 　　# Concatenate $b and $c = BBCC
$a = $b x $c; 　　# $b repeated $c times

?

【Perl的赋值语句】

$a = $b; 　　　　　# Assign $b to $a
$a += $b; # Add $b to $a　　（算数运算）
$a -= $b; # Subtract $b from $a
$a .= $b; # Append $b onto $a （字符运算）

【?互操作性】

?

$b = 'Pear';
$c = 'CC';
$a = 'Apple';

print $a.' and '.$b;?
print "n";　　　　#?制表符（t） 换行（n）
print '$a and $b';
print "n";
print "$a and $b";

?

【数组变量】

数组通过以0开始的索引进行访问，方括号内为索引值

@List = ("1",2,'3');

print @List;

> 123

?

【?数组 赋值/删减】?

?

@List = ("1",'3',"Array");

print @List;

print "n";

print @array;

>123Array

? 56789101112131415

?

# push Statement.

push(@List,"Added");

print @List;

print "n";

push(@List,@array);

print @List;

>123Array

? 123Array56789101112131415

?

# pop Statement.

?

@List = ("1","Array");
@array = (5..15);
push(@List,@array);
$e =? pop(@List);
$f =? pop(@List);

print $f;
print "n";
print @List;
print "n";
$f = @List;
print $f;

?

> 14

???123Array568910111213

?? 13

?

?# 数组也可以用来为多个标量进行赋值

?

@List = ("1",@array);
$e =? pop(@List);
$f =? pop(@List);
print "n";
print $e;
print "n";
print $f;
print "n";

($e,$f,$a) = @List;???? ?# 按照数组顺序项给变量赋值。

print "n";
print $e;
print "n";
print $f;
print "n";
print $a;

?

?

> 15

?? 14

???1

?? 2

?? 3

?

# 最后，你可能想知道列表中最后一个元素的索引值，可以用这个表达式：

print $#List;

> 12;

?

?($a,$b) = ($c,$d); # Same as $a=$c; $b=$d;($a,$b) = @food; # $a and $b are the first two items of @food.($a,@somefood) = @food; # $a is the first item of @food?， @somefood is a list of the?others.(@somefood,$a) = @food; # @somefood is @food and?$a is undefined.