Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
Generate new list using map in Perl
Answer:
The Perl's map function is superb cool for generating new list based on an existing list.
1. Generate new array based on an existing array
my @new = map {$_ * 2} (1, 2, 3);
# @new contains 2, 4, 6
2. Generate new hash based on an existing array
my %new = map {$_ => 1} (1,2,3);
# %new contains a hash...
# {
# '1' => 1,
# '3' => 1,
# '2' => 1
# };
Generate UUID in PHP
Answer:
To generate UUID in PHP, you can try the script below:
<?php
function uuid($prefix = '') {
$chars = md5(uniqid(mt_rand(), true));
$uuid = substr($chars,0,8) . '-';
$uuid .= substr($chars,8,4) . '-';
$uuid .= substr($chars,12,4) . '-';
$uuid .= substr($chars,16,4) . '-';
$uuid .= substr($chars,20,12);
return $prefix . $uuid;
}
echo uuid();
It shows something like the following when executed:
c664b9b4-6c44-c8d9-acf9-93ef0e11e435
Clone an object in PHP
Answer:
It is easy to clone an object in PHP, using the following method.
<?php
$obj = new stdClass();
$obj->foo = "foo";
$obj->bar = "bar";
$new_obj = clone $obj;
var_dump ( new_obj );
It will print out...
object(stdClass)#2 (2) {
["foo"]=>
string(3) "foo"
["bar"]=>
string(3) "bar"
}Filter a list using grep in Perl
Answer:
The Perl's grep function is very useful for list filtering.
E.g. Array filtering
my @new = grep {$_ > 1} (1,2,3);
# @new contains 2, 3 only
Create an array containing a range of elements in PHP
Answer:
It is easy to create an array using the range() function, e.g.
<?php
foreach (range(0, 10) as $number) {
echo $number, " ";
}
It shows following when executed:
0 1 2 3 4 5 6 7 8 9 10
