/prog/ - Programming

How would I vertically flip text in a 2d array in java?

;; Programming Exercise 12
;; Check for structural equality of a list.
;; (a, b = lists to compare)
(defun structurally-eq (a b)
    (cond (and (a b);both lists are empty.
        t)
    (xor (a b)      ;only one of the lists are empty.
        f)
    (and ('(cdr a) '(cdr b)) ;first of both is an atom.
        (structurally-eq (cdr a) (cdr b)))
    (xor ('(cdr a) '(cdr b)) ;only one of first out of both is an atom.
        f)
    (else
     (and (structurally-eq (car a) (car b))   ;recursion over the car of each list
          (structurally-eq (cdr a) (cdr b)))));recursion over the cdr of each list
)

I get *** - SYSTEM::%EXPAND-FORM: '(CDR A) should be a lambda expression, which I don't understand why.

>>2208

Why have you quoted those cdrs?

>>2214

Mostly because the language confuses me. I looked up my error on stackoverflow and there was a mention to add a '.

But off here

https://en.wikibooks.org/wiki/Common_Lisp/First_steps/Beginner_tutorial

I don't have a clear idea of what quote is for.

(There's another error like "variable AND has no value" if I remove it.)

>>2208

;; Check for structural equality of a list.
;; (a, b = lists to compare)
(defun structurally-eq (a b)
    ;both lists are empty
    (cond ((and (eq nil a) (eq nil b)) t)
    ;only one list is empty.
        ((xor (eq nil a) (eq nil b)) nil)
    ;if the `car` part of both lists is an atom
        ((and (atom (car a)) (atom (car b)))
            (structurally-eq (cdr a) (cdr b)))
    ;one of the car parts of the list is a sub-list.
        ((xor (atom (car a)) (atom (car b))) nil)
    ;otherwise recursion over 'car' and 'cdr' of both lists.
        ((and (structurally-eq (car a) (car b))
            (structurally-eq (cdr a) (cdr b)))))
)

Okay, after some rest and breakfast, got it; kind of, because I thought f was for false, but it gave me "COND: variable f has no value" before I swapped out the f's with nils.

>>2214

he's trolling

Really quick Javascript question here:

Is there any kind of performance difference or any kind of benefit/handicap to doing one above another:

thing.other.object.related.inside.outside.a = 1;
thing.other.object.related.inside.outside.b = 2;
thing.other.object.related.inside.outside.c = 3;
thing.other.object.related.inside.outside.d = 4;
thing.other.object.related.inside.outside.e = 5;
…

var thevalue = thing.other.object.related.inside.outside;
thevalue.a = 1;
thevalue.b = 2;
thevalue.c = 3;
thevalue.d = 4;
thevalue.e = 5;
…

>>2346

>Is there any kind of performance difference or any kind of benefit/handicap to doing one above another:

Fair warning: I am not a JS wizard

You'd have to benchmark it to be sure, but in general, the second way should be somewhat faster (in unoptimized JS),

since it removes the need to look up 'thing.other.object.related.inside.outside' each time.

JIT compilers (i.e. Google's V8) could (probably) do that optimization themselves, though.

>>2349

>in general, the second way should be somewhat faster (in unoptimized JS), since it removes the need to look up 'thing.other.object.related.inside.outside' each time.

That's what I was thinking about, thanks

I can't wrap my fucking head around javascript and how shit works really.

I have several inputs: radio buttons, list boxes, text boxes (none of them have ID), I need to do a function to validate they are not empty .

so

 <script type="text/javascript" >		function validar()
               {
		 var aux=document.getElementsByTagName("input");
		}
		</script>

that's all i got of my function so far, but I have zero idea how to check if every input has no text or nothing has been selected.

>>2354

probably something like aux.isEmpty() or getText() or whatever. i'm sure the answer is just a google search away.

but before you write javascript eyecandy make sure your website has a working fallback mode with pure html and css.

>>2354

Google, nigger.

http://jqueryvalidation.org/

>>2354

getElementsByTagName() returns an Array.

I'm not sure if javascript has a foreach loop like java, but I guess you could do something like

for (var i = 0; i < aux.length(); i++) if (aux[i].value == '') alert('error');

How do I make a GUI from scratch in ruby?

>>2406

Web or native?

https://www.ruby-toolbox.com/categories/GUI_Frameworks

>>901

>facepalm

back to reddit

>>1040

Nigger do yourself a favor and right click the window border of your console, click properties and change the font to something schwayer than that

hey all

i'm using the following code to convert rgb to hex

'{:02x}{:02x}{:02x}'.format(r,g,b)

Now I need to be able to convert from hex back to rgb. I've seen some weird ways of doing this with ord and map but I was wondering if anyone could think of a simple way to do it with format()

thanks in advance

Hey guys. I can't get out of a shitty regex+PHP situation, figured I'd ask you.

Short story: I have a few regexes which I'm using to get data from whois responses. But in 95% of cases, they're not picking up anything even if the same text (newlines stripped, commas stripped, only whitespace - I'm getting it by printing it after I've retrieved and stripped it) on regex101.com gives me the correct matches.

In another case it returns the correct match…and text I'm not interested into.

This does not return anything, even if it should:

preg_match('~[Registrar|Registrar Organization]:\s*(.*?)(Sponsoring|Registrar|\(|Name|\[)~si',$text,$registrar_name);

While this returns date, time and "Expire Date:" string:

preg_match('~Expir.*?Date:\s*([[:digit:]]*-[[:digit:]]*-[[:digit:]]*)~si',$text,$expir_date);

I've tried looking at $return_array[0] and [1], also checking with var_dump().

Error checking returns in ALL CASES preg_no_error.

Haven't found anything useful on stack overflow, and my googlefu didn't help either.

Any of you has an idea as to what I'm doing wrong?

/* Enter your own Javascript code here... */
/* You can include JS files from remote servers, for example: */
/* load_js("http://example.com/script.js"); */

// put 8archive.moe links after every post
var intros = getElementsByClassName("intro");
var 8archive_anchor = document.createElement("a");
8archive_anchor.appendChild(document.createTextNode("Archive"));
var board = window.location.pathname.slice(1);
board = board.slice(0, board.indexOf('/'));
var threadNo = window.location.pathname.slice(window.location.pathname.lastIndexOf('/')+1, -5);
var 8archive_url = "http://8archive.moe/"+board+"/thread/"+threadNo;
for (var i = 0; i < intros.length; i++) {
	var postNo = intros[i].firstElementChild.id;
	8archive_anchor.setAttribute("href", 8archive_url+"/#"+postNo);
	intros[i].appendChild(8archive_anchor);
}

>>2589

help please?

>>2589

help please?

>>2603

>>2601

please ignore accidental duplicate

>>2589

1. don't use js

2. debug each variable. print them out or inspect them, figure out which one doesn't get set properly.

1. don't use js

What the hell does RAII mean and why do people talk about it constantly like it's hot shit when talking about C++?

I've been reading a bit on it and, from what I understood, I think it means that resources are allocated during initialization of objects, and it is destroyed once the scope is exited.

What's so special about that and why does it warrant a fancy name? I thought it was the point of stack-based allocation, and while I thought C did the same exact thing, apparently it doesn't. Why isn't C's stack based allocation considered RAII?

>>2663

RAII is not just removing stack memory at the end of scope, I'd say every language does that.

RAII is about automatically calling destructor functions of objects when you hit the end of the scope they're defined in.

An equivalent in C would be automatically calling fclose on a FILE* at the end of scope.

writing a small tile-based game engine. I can't quite figure out why I can't list the rows after I've generated them. Any ideas would be much appreciated, I feel it's stupid simple.

#!/usr/bin/python2.7
from random import randint
import os
import sys
import time
def gentile():
        global tid
        r1 = "."
        r2 = "o"
        seed = randint(0,10)
        if seed <= 9:
                tid = r1
        if seed == 10:
                tid = r2
def main():
        width = 10
        height = 10
        termwidth = width * 2 + 1
        print "-" * termwidth
        count = 1
        for i in range(height):
                rows = []
                rows.append("\n ")
                for i in range(width):
                        gentile()
                        rows.append(tid)
                        print(rows[i]),
                count = count + 1
        print "\n"
        print "-" * termwidth
        count = 0
        for i in range(height): #Can't even
                print(rows[count:count + 10]),
                print "\n"
                count =+ 1
main()

>>2687

for i in range(height):
                rows = [] # <- Because 'rows' is local to the 'for' loop here.
                               # You must declare it outside of the loop.
                rows.append("\n ")
                for i in range(width):
                        gentile()
                        rows.append(tid)
                        print(rows[i]),
                count = count + 1

>>2691

Thank you! ended up figuring it out myself, it's going along well though, added in a player and making him move at the moment!

>>2654

Thanks, I got it to work now

>1.

why?

>>2700

(not him) JS is a really shitty language, but if you want to do client-side scripting you pretty much have to use it. Use it if you need it, otherwise stay away from it

>>1640

>n * (n / 10)

Why use a parenthesis at all? Multiplication and division are commutative

It's the same as n*n/10

>>2716

just use 0.1 * n * n and ignore floating point

QT or GTK?

>>2729

Qt is much nicer to work with. It's not even a fair comparison. GTK is kind of shitty. However, Qt is best used with C++, so if you're adamantly anti-C++, then maybe GTK would be better.

I'll also through in that wxWidgets is a really nice toolkit, especially if you want to use a higher-level language. It has pretty good bindings to Python, Ruby, Perl, and even Common Lisp.