perl的array和map/hash
一 array
1）实例
use strict;
use warnings;
my @myarray = (123,"hello", 456, 'guy');
foreach(@myarray)
{
print "$_ " ;
}
print "\n";
foreach my $item (@myarray)
{
print "$item " ;
}
print "\n";
for(my $i = 0; $i <scalar(@myarray); $i++)
{
print "$myarray[$i]" . " ";
}
print "\n";
for(0..($#myarray))
{
print "$myarray[$_]" . " ";
}
print "\n";
@myarray = (@myarray, 789);
print "@myarray\n" ;
push(@myarray,"gril");
print "@myarray\n" ;
unshift(@myarray, '000');
print "@myarray\n" ;
delete $myarray;
print "@myarray\n" ;
2）函数，如下：
3）注释：
1】使用@定义array，使用array的item时$array；
2】使用scalar来获得array的size；
3】$#获得最大的index，即size-1；
4】$_在for和foreach中表示当前item；
5】push/pop用来在array的最后加入和弹出item；
6】shift/unshift用来在array的前面删除和插入item；
7】split/john用来实现array和string间的转化；
8】delete可以用来删除item，例如delete $myarray;
二 map/hash
1) 实例：
use strict;
use warnings;
my %myhash = ('k1',100,'k2',200);
# my %myhash = (k1=>100,k2=>200);
print %myhash ;
print "\n";
$myhash{'k3'} = 300;
$myhash{'k4'} = 400;
print %myhash ;
print "\n";
foreach my $key (keys %myhash)
{
print $key . " indexes ".$myhash{$key}."\n";
}
foreach my $value (values %myhash)
{
print $value ."\n";
}
while((my $key, my $value)= each(%myhash))
{
print "$key indexes $value \n"
}
if(exists $myhash{'k1'}) {print "k1 is exist\n";}
delete $myhash{'k1'};
print %myhash ;
print "\n" ;
2）函数，如下：
3）注释：
1】%用来定义map/hash；
2】对单个的key赋值是使用$,例如$myhash{'k3'} = 300;
3】keys获得所有的keys到array；
4】values获得所有的values到array；
5】迭代，每次返回一对key/value;
6】exists用来判断某个key是否存在；
7】delete用来删除指定的key，同时对应的value也被删除；
三 总
Array Functions
@array = ( ); Defines an empty array
@array = (“a”, “b”, “c”); Defines an array with values
$array The first element of @array
$array = a; Sets the first element of @array to a
@array Array slice - returns a list containing the 3rd thru 5th
elements of @array
scalar(@array) Returns the number of elements in @array
$#array The index of the last element in @array
grep(/pattern/, @array) Returns a list of the items in @array that matched
/pattern/
join(expr, @array) Joins @array into a single string separated by expr
push(@array, $var) Adds $var to @array
pop(@array) Removes last element of @array and returns it
reverse(@array) Returns @array in reverse order
shift(@array) Removes first element of @array and returns it
sort(@array) Returns alphabetically sorted @array
sort({$a<=>$b}, @array) Returns numerically sorted @array
Hash Functions
%hash = ( ); Defines an empty hash
%hash = (a => 1, b=>2); Defines a hash with values
$hash{$key} The value referred to by this $key
$hash{$key} = $value; Sets the value referred to by $key
exists $hash{$key} True if the key/value pair exists
delete $hash{$key} Deletes the key/value pair specified by $key
keys %hash Returns a list of the hash keys values %hash Returns a list of the hash values
完！
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