Comparing PHP, Perl, Python and Ruby

by charlax • 14 years ago

382 87 14 years ago

verelo• 14 years ago

This is great. Very handy for explaining to others the differences between various languages, and surprisingly enough until you get into the array functions i'm starting to feel like PHP isn't really that messy since reading this!

Thanks for sharing, ill pass it on whenever a comparison is needed.

leftnode• 14 years ago

PHP5.4 also has the short syntax array initializer:

    $array = [1, 2, 3];

Edit: While PHP still has it's fair share of issues, a lot of the same complaints people had 5-8 years ago aren't valid, and it probably has no more or less oddities than any other scripting language at this point.

jacques_chester4• 14 years ago

The problem with PHP is that 99.99% of the code in circulation today isn't the shinier cleaned-up versions. It's PHP4 and PHP 5.0 and it's still chock-a-block with the storied mind-bending nastiness of yore.

youlost_thegame3• 14 years ago

Very, very thorough. A great resource, thanks!

youlost_thegame3• 14 years ago

Wait... there's more on the homepage! http://hyperpolyglot.org/

youlost_thegame3• 14 years ago

  Empty comments can be ok if they're positive. There's 
  nothing wrong with submitting a comment saying just 
  "Thanks." What we especially discourage are comments that 
  are empty and negative—comments that are mere name-calling.

--http://ycombinator.com/newswelcome.html

rll• 14 years ago

Note that anywhere you see array() in that list for PHP 5.4 you can replace it with [ ]'s. So the example that has:

  $a = array(1,2,array(3,4));

becomes:

  $a = [1,2,[3,4]];

Also

0b101010

works in 5.4.

Klinky2• 14 years ago

True, but PHP 5.4 doesn't even have a stable release yet & many people haven't even adopted 5.3.

maratd• 14 years ago

Just an FYI, but they are at the end of their testing the RC of 5.4, so it should be declared stable in about 2-3 weeks.

robryan4• 14 years ago

5.3 Come out in 2009, I has a small list of backwards compatibility breaking changes (http://www.php.net/manual/en/migration53.incompatible.php), no reason for anyone really not to have adopted it.

wildtype2• 14 years ago

Today, PHP 5.4 are released as stable.

powersurge3602• 14 years ago

PHP repl is actually php -a

mikey_p• 14 years ago

Note that this is not a traditional repl in the style of of Python or IRB that evaluates each line individually. With php -a you have to enter an entire script, and then exit to run it, and which point you can no longer interact with the variables, etc. Also it's super backwards in that you need to add <?php tags to turn interpretation on.

If you really want a repl that's useful for PHP check out http://www.phpsh.org/ by Facebook.

powersurge3602• 14 years ago

No, you can do evaluation line by line, but it isn't exactly nice. Just typing php forces you to type in the entire script.

methoddk• 14 years ago

Bookmarked and forever using this to explain the differences between these. Thanks for the awesome resource!

snampall• 14 years ago

Nice. Useful and handy.

devy• 14 years ago

Even though there is no native "switch" statement in Python, the same control flow structure can be done with a dict construct:

http://simonwillison.net/2004/may/7/switch/

hack_edu• 14 years ago

Whenever the debate comes up in official channels, there is near-unanimous support for omitting it.

tikhonj• 14 years ago

Here's a simpler comparison with way more langauges: http://rigaux.org/language-study/syntax-across-languages/Str...

raymondh• 14 years ago

This is a wonderful recap of the different ways of expressing the same idea in different languages. It is a fine Rosetta Stone.

That being said, it would also be useful to characterize features that are completely unique to a given language. For example, Python has 1) a unique and powerful version of super() for working with multiple inheritance; 2) it has generators (the yield statement) that allows state to be suspended and restarted (and allows data and/or exceptions to be passed back in to the generator); 3) the with-statement for managing contexts and for providing a new way to factor code; 4) easy-to-write class and function decorators; 5) metaclass support that provides full control over the creation of classes; 6) and descriptors for fine-control over attribute/method binding behavior.

Collectively, these capabilities make the language more than just another syntax for expressing the same ideas as other languages.

jrockway4• 14 years ago

That being said, it would also be useful to characterize features that are completely unique to a given language.

Perl has all these features.

1) a unique and powerful version of super() for working with multiple inheritance

Perl (with Moose) has before, after, around, override, and augment in addition to super. And, it has "Roles" so you don't have to resort to hacks like multiple inheritance to implement mixins or interfaces.

2) it has generators (the yield statement) that allows state to be suspended and restarted (and allows data and/or exceptions to be passed back in to the generator)

Perl has the library Coro, which allows multiple Perl and C stacks. With this coroutine and call-with-current-continuation are implemented.

3) the with-statement for managing contexts and for providing a new way to factor code

Perl has scope a few implementations of scope guards; Guard and Scope::Guard. It's not quite the same as with, because with's semantics around:

   with open_file('foo') as f:
       return f

are unclear (f is closed but the object still exists). Perl mixes

   sub x {
      my $f = file('foo')->openr;
      return $f; # $f is still open and ready for reading by the caller
   }

Emulating Python is still possible, however:

   sub x {
       my $f = file('foo')->openr;
       scope_guard { $f->close }
       return $f; # caller gets a closed file object
   }

4) easy-to-write class and function decorators

This you don't really get, though you do get all of the things I've seen them used for in Python. You can even hack Perl syntax in a lexical scope, but that's evil so I will pretend it's impossible :)

5) metaclass support that provides full control over the creation of classes; 6) and descriptors for fine-control over attribute/method binding behavior

Moose. And unlike Python, there are libraries that take advantage of this to provide tiny bits of OO functionality that you can pick and choose from. Look on CPAN for a MooseX:: module, and chances are that the set of libraries you choose to use to augment a class will all work together.

The difference between Perl and Python is that Perl's features are implemented as modules, while Python's features are implemented in the core. That means that if you come up with a good idea, you can start using (and sharing) it immediately, while with Python, you have to wait until the next major release.

neilk• 14 years ago

It also means you have to stumble upon Moose to start using objects in a reasonably sane way. The average new Perl programmer is not going to go looking for a library that does object-oriented behavior until it's too late. They'll probably have some crazy idea that the language should be doing OO for them.

If you were to navigate a largish Perl codebase today, you'd encounter the old-school bless, Moose trickiness, and all kinds of variants on these themes. Extremely clever stuff that Damian Conway would give you a gold star for.

As usual Perl gives you everything you want, unless what you wanted was simplicity or standardization.

smsm423• 14 years ago

I'm pretty sure you can do the same generator does with iterators in PHP. Traits in PHP 5.4 probably cover most of use cases where you may want multiple inheritance. Decorators are superior in Python though, no real replacement for it in PHP.

berntb3• 14 years ago

A very useful page if you know one or two of those languages and need to do something in another one.

A suggestion: For people doing some work in Perl, a review of the OO syntax might be critical. Both Moose and the old way.

A note, re the repl part: I don't use a repl for Perl, I just write one liners in shell. Afaik, Perl is the best command line tool that exist, it is even a superset of awk.

Edit: For named parameters the page might want to reference one of the CPAN modules doing that. Same goes for exceptions. The use of do to create blocks most everywhere might also be noted in e.g. the ternary operator. Unicode support should probably also be discussed. And so on.

rwmj• 14 years ago

[I wonder if this is a personal watershed for Hacker News?]

These languages are essentially the same thing. I often write code in at least 3 of these languages most days, and I simply translate the minor differences between them in my head.

"Hyperpolyglot" -- excess in many tongues -- I don't think so.

Learn at least some static languages, assembler and some functional languages, and then post something interesting on HN.

Well, I have plenty of karma to waste on noobs.

mattdeboard• 14 years ago

Nothing I love more than watching someone try way too hard to act "grizzled" and in the process make an idiot out of themselves.

http://hyperpolyglot.org/

whateverer2• 14 years ago

Was that in response to his exhortation to learn different languages, or do you actually believe that Perl and its self-proclaimed successors have any profound differences?

rlander• 14 years ago

I take it you spent more time writing your rant than actually navigating the site you're criticizing. Please take a look at the index.

joewadcan• 14 years ago

Very helpful!! Like a quick & easy Rosetta stone

ars• 14 years ago

Previous discussion: http://news.ycombinator.com/item?id=2882070 with lots of bug reports. I wonder if they incorporated all the changes suggested.

alexm920• 14 years ago

Wonderful reference for comparison! I admittedly haven't had time to pursue the whole table, but wanted to point out that there is indeed an increment and decrement in python:

x += 1

x -= 1

mistercow• 14 years ago

They list those under "compound assignment operators", which makes sense given that += and -= are found in all of these languages. It's also worth noting that compound assignment operators do not form expressions in Python. So "i++" in PHP/Perl/Ruby is very different from "i += 1" in Python.

balloot• 14 years ago

An increment/decrement operator is unary and doesn't give you the ability to change the value by any more than one.

alberth• 14 years ago

Wish Lua was added to the list.

Edit: Found Lua compared on the same site here: http://hyperpolyglot.org/embeddable

citizenkeys• 14 years ago

sed begat awk.

awk begat perl.

perl begat python and ruby.

python will get you a job at google.

ruby will get you a job at twitter.

php will get you a job at facebook.

singingfish• 14 years ago

perl will get you a job running the internet ;)

jrockway4• 14 years ago

python will get you a job at google

I used Perl for all of my job interviews at Google, and I work at Google.

But Google is a Java and C++ company, with some Python around (but a bit of an anti-scripting culture as well).

wildtype2• 14 years ago

ruby will get you a job at twitter.

I heard that twitter are moving from ruby to scala.

desireco42• 14 years ago

that was more then a year or two ago, they changed their mind in the meantime. they do have some cool software developed in scala I think.

garindra• 14 years ago

I'm pretty sure the companies that you mentioned know enough about recruiting that they won't hire people solely based on the languages that they know. Skills transcend programming languages; especially among those similar-enough scripting languages.

smsm423• 14 years ago

Unfortunately tests page for PHP does not mention PHPUnit: http://www.phpunit.de/manual/3.6/en/index.html which is the best solution for testing in PHP. Neither it mentions xdebug for debugging and xhprof for profiling.

Arabian• 14 years ago

The Perl described in this article is COMPLETE SHIT. He calls deprecated and improper libs for some functions, unnecessary libs in others, assumes improper or unoptimal syntax in other examples. The list goes on. Learn languages before releasing articles on them.

He never even uses Perl's foreach in equivalency examples!! WTF.

masklinn• 14 years ago

Not sure it's a "he", it's a wiki-type thingie.

Also, you can report bugs on the table if things are not correct.

notJim2• 14 years ago

This is a really great effort, but I noticed a handful of areas where the PHP example was off. I wonder if people with more experience with the other languages noticed the same thing for their language.

Some examples:

Null test:

    $var === null // omitted
    isset($var) // actually checks if $var exists and is not null (apparently--
        I actually didn't know about the not null part)

Undefined variable access: it's a notice. Many people consider it best practice in PHP to treat notices as error, because things like this are notices.

Add time duration

    strtotime('+10 minutes') is more typical than the objects

Array out of bounds behavior again issues a notice.

MattBearman• 14 years ago

I noticed that block statements were missing from PHP, eg: using if(): ... endif; etc. instead of if(){ ... }

jablan• 14 years ago

"Passing by reference" section is wrong about Ruby (not sure about Python). Ruby passes everything by reference, it's only that integers are immutable so that the function can't alter them. Strings, though, are mutable:

  def foo s
    s.concat 'foo'
  end
  a = 'bar'
  foo a
  a
  # => "barfoo"

rplnt• 14 years ago

In python, strings are immutable as well.

joesb• 14 years ago

Niether Ruby or Python do "pass by reference".

They both do "pass reference by value". Which is a big difference.

sciurus• 14 years ago

Not exactly. Let's tweak your example to create a new object in your method.

  def foo s
    s = 'foo'
  end
  a = 'bar'
  foo a
  puts a
  # => bar

The assignment in the method doesn't change the object you "passed" in. Rather than passing by reference, think of Ruby as passing the value of a reference.

For more examples and explanation, see http://khelll.com/blog/ruby/ruby-pass-by-value-or-by-referen...

vidarh2• 14 years ago

Well, integers are immutable (and conceptually a singleton per value) unless you override stuff in FixNum and add instance variables. Here's an evil example that works at least in MRI 1.8.6:

    class Fixnum

      alias :realplus :+
    
      def + b
        @a ||= 0
        @a = @a.realplus(b)
        self.realplus(@a)
      end
    end

The integer value itself is immutable, though.

Of course all hell will break loose and adding instance variables in certain classes like Fixnum will be extra slow (as if there aren't enough other reasons not to), since MRI uses type-tagging for Fixnum, Symbol and a few others, and so since they're not "real" objects, if you do anything that requires one, it creates one that's stored in a hash table.

laichzeit0• 14 years ago

Perl's treatment of regex still trumps all. It's so pleasant to use in so many ways. It's for this reason alone I will probably never bother "switching" to Python or Ruby.

crusso• 14 years ago

Since Ruby copies Perl's regex shortcuts (blah =~ /matchme/), what's the problem?

kirinan2• 14 years ago

Very good comparison between all the languages, and like other people said: a nice Rosetta stone. With that said, it would be very useful to add a comparison of the database layer syntax as that it is, at least for a me, a common task in all of the scripting languages. I also agree with the comments about adding the features that are unique to the languages, as that would be extremely helpful.

pavelkaroukin• 14 years ago

there are quite a few options for syntax already in the mix, that people noticed already. If we will add DB-related stuff, it will confuse even more - too many options available in each language.

kirinan2• 14 years ago

Great point! Thanks for the response, and it makes sense.

Comparing PHP, Perl, Python and Ruby

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