SHUT THE FUCK UP AND WRITE SOME CODE

containers

Perl Ruby PHP Python

スクリプト言語の比較

http://hyperpolyglot.org/scripting を参考に、スクリプト言語の勉強をしてまいります。

containers

array literal

@nums = (1,2,3,4);

<?php
$nums = array(1,2,3,4);
?>

nums = [1,2,3,4]

nums = [1,2,3,4]

array size

$#nums + 1 or
scalar(@nums)

<?php
count($nums)
?>

len(nums)

nums.size
nums.length # same as size

array lookup

$nums[0]

<?php
$nums[0]
?>

nums[0]

nums[0]

array slice

@nums[1..2]

<?php
# 3rd arg is length of slice:
array_slice($nums,1,2)
?>

nums[1:3]

nums[1..2]

manipulate back of array

@a = (6,7,8);
push @a, 9;
pop @a;

<?php
$a = array(6,7,8);
array_push($a, 9);
array_pop($a);
?>

a = [6,7,8]
a.append(9)
a.pop()

a = [6,7,8]
a.push(9)
a << 9 # same as push
a.pop

manipulate front of array

@a = (6,7,8);
unshift @a, 5;
shift @a;

<?php
$a = array(6,7,8);
array_unshift($a, 5);
array_shift($a);
?>

a = [6,7,8]
a.insert(0,5)
a.pop(0)

a = [6,7,8]
a.unshift(5)
a.shift

array concatenation

@a = (1,2,3);
@b = (@a,(4,5,6));
push @a, (4,5,6);

<?php
$a = array(1,2,3);
$b = array_merge($a,array(4,5,6));
$a = array_merge($a,array(4,5,6));
?>

a = [1,2,3]
b = a + [4,5,6]
a.extend([4,5,6])

a = [1,2,3]
b = a + [4,5,6]
a.concat([4,5,6])

address copy, shallow copy, deep copy

@a = (1,2,[3,4]);
$b = \@a;
@c = @a;
none

<?php
$a = (1,2,array(3,4));
$b =& $a;
none
$d = $a;
?>

a = [1,2,[3,4]]
b = a
c = list(a)
import copy
d = copy.deepcopy(a)

a = [1,2,[3,4]]
b = a
c = a.dup
d = Marshal.load(Marshal.dump(a))

arrays as function arguments



each element passed as

separate argument;

use reference to pass

array as single argument



parameter contains

deep copy



parameter contains

address copy



parameter contains

address copy

array iteration

for $i (1 2 3) {
  print "$i\n"
}

<?php
foreach (array(1,2,3) as $i) {
  echo "$i\n";
}
?>

for i in [1,2,3]:
  print(i)

[1,2,3].each { |i|
  puts I
}

indexed array iteration

@a = ('a','b','c');
for ($i=0; $i<scalar(@a); $i++) {
  print "$a[$i] at index $i\n";
};

<?php
$a = array('a','b','c');
foreach ($a as $i => $c) {
  echo "$c at index $i\n";
}
?>

for i, c in enumerate(['a','b','c']):
  print("%s at index %d" % (c, i))

a = ['a','b','c']
a.each_with_index do |c,i|
  puts "#{c} at index #{i}"
end

sort

@a = (3,1,4,2);
sort @a;
@a = sort @a;
sort { $a <=> $b } @a;

<?php
$a = array(3,1,4,2);
none
sort($a);
?>

a = [3,1,4,2]
sorted(a)
a.sort()

a = [3,1,4,2]
a.sort
a.sort!
a.sort { |m,n| m <=> n}

reverse

@a = (1,2,3);
reverse @a;
@a = reverse @a;

<?php
$a = array(1,2,3);
array_reverse($a);
$a = array_reverse($a);
?>

a = [1,2,3]
list(reversed([1,2,3]))
a.reverse()

a = [1,2,3]
a.reverse
a.reverse!

membership

grep { 7 == $_ } @nums

<?php
in_array(7, $nums)
?>

7 in nums

nums.include?(7)

intersection

<?php
$a = array(1,2);
$b = array(2,3,4)
array_intersect($a, $b)
?>

set.intersection(set([1,2]),
  set([2,3,4]))

[1,2] & [2,3,4]

union

<?php
?>

set.union(set([1,2]),set([2,3,4]))

[1,2] | [2,3,4]

map

map { $_ * $_ } (1,2,3)

<?php
$t2 = create_function('$x', 'return $x*$x;')
array_map($t2, array(1,2,3))
?>

map(lambda x: x * x, [1,2,3])
# or use list comprehension:
[x*x for x in [1,2,3]]

[1,2,3].map { |o| o*o }

filter

grep { $_ > 1 } (1,2,3)

<?php
$gt1 = create_function('$x','return $x>1;');
array_filter( array(1,2,3), $gt1)
?>

filter(lambda x: x > 1,[1,2,3])
# or use list comprehension:
[x for x in [1,2,3] if x > 1]

[1,2,3].select { |o| o > 1 }

reduce

reduce { $a + $b } 0, (1,2,3)

<?php
$add = create_function('$a,$b','return $a+$b;');
array_reduce(array(1,2,3),$add,0)
?>

# import needed in python 3 only
import reduce from functools
reduce(lambda x,y:x+y,[1,2,3],0)

[1,2,3].inject(0) { |m,o| m+o }

universal test



none, use grep



none, use array_filter

all(i%2 == 0 for i in [1,2,3,4])

[1,2,3,4].all? {|i| i.even? }

existential test



none, use grep



none, use array_filter

any(i%2 == 0 for i in [1,2,3,4])

[1,2,3,4].any? {|i| i.even? }

map literal

%h = ( 't' => 1, 'f' => 0 );

<?php
$h = array('t' => 1, 'f' => 0);
?>

h = { 't':1, 'f':0 }

h = { 't' => 1, 'f' => 0 }

map size

scalar(keys %h)

<?php
count($h)
?>

len(h)

h.size
h.length # same as size

map lookup

$h{'t'}

<?php
$h['t']
?>

h['t']

h['t']

is map key present

defined($h{'y'})

<?php
array_key_exists('y',$h);
?>

'y' in h

h.has_key?('y')

map iteration

while ( ($k, $v) = each %h ) {

<?php
foreach ($h as $k => $v ) {
?>

# python 2:
for k,v in h.iteritems():
  code
# python 3:
for k,v in h.items():
  code

h.each { |k,v| code }

keys and values of map as arrays

keys %h
values %h

<?php
array_keys($h)
array_values($h)
?>

h.keys()
h.values()

h.keys
h.values

out of bounds behavior

undef

<?php
NULL
?>



raises IndexError or KeyError

nil

スクリプト言語の比較 - 目次

arithmetic and logic

execution control

environment and i/o

libraries and modules

reflection and hooks