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How to implement an abstract class in ruby?

...clarative about which methods are abstract: module Abstract def abstract_methods(*args) args.each do |name| class_eval(<<-END, __FILE__, __LINE__) def #{name}(*args) raise NotImplementedError.new("You must implement #{name}.") end END # import...
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Can iterators be reset in Python?

...r protocol is very simple, and only provides one single method (.next() or __next__()), and no method to reset an iterator in general. The common pattern is to instead create a new iterator using the same procedure again. If you want to "save off" an iterator so that you can go back to its beginni...
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How to solve PHP error 'Notice: Array to string conversion in…'

I have a PHP file that tries to echo a $_POST and I get an error, here is the code: 5 Answers ...
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Passing additional variables from command line to make

...all of them contain some certain kind of assert stuff and you just want to test them all) share | improve this answer | follow | ...
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Calculating a directory's size using Python?

... This walks all sub-directories; summing file sizes: import os def get_size(start_path = '.'): total_size = 0 for dirpath, dirnames, filenames in os.walk(start_path): for f in filenames: fp = os.path.join(dirpath, f) # skip if it is symbolic link ...
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What is x after “x = x++”?

...alidate what I said would be to consult the JLS. Your compile / decompile test only shows that what I said is valid for one Java compiler. Others could (hypothetically) behave differently ... except that the JLS doesn't allow that. – Stephen C Aug 24 '12 at 1...
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Django get the static files URL in view

... here's another way! (tested on Django 1.6) from django.contrib.staticfiles.storage import staticfiles_storage staticfiles_storage.url(path) share | ...
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How to save an HTML5 Canvas as an image on a server?

... a hidden field. After that I submit the form. document.getElementById('my_hidden').value = canvas.toDataURL('image/png'); document.forms["form1"].submit(); 4) When the form is submited I have this small php script: <?php $upload_dir = somehow_get_upload_dir(); //implement this function you...
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Using braces with dynamic variable names in PHP

...rom phpNET manual php.net/manual/ru/language.variables.variable.php $price_for_monday = 10; $price_for_tuesday = 20; $today = 'tuesday'; $price_for_today = ${ 'price_for_' . $today}; echo $price_for_today; // will return 20 – Vladimir Ch Apr 20 '18 at 21:08 ...
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Is “else if” a single keyword?

...nt i; } So how is your slightly extended example parsed? if statement_0; else if statement_1; else if statement_2 ; will be parsed like this: if { statement_0; } else { if { statement_1; } else { if { statement_2 ; ...