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What are the differences between Perl, Python, AWK and sed? [closed]
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In order of appearance, the languages are sed, awk, perl, python.
The sed program is a stream editor and is designed to apply the actions from a script to each line (or, more generally, to specified ranges of lines) of the inpu...
How do I get the object if it exists, or None if it does not exist?
...odels.Manager, create a safe_get like the code above and use that manager for my models. That way you can write: SomeModel.objects.safe_get(foo='bar').
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How using try catch for exception handling is best practice
...e maintaining my colleague's code from even someone who claims to be a senior developer, I often see the following code:
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Regular expression for letters, numbers and - _
...m):
^[a-zA-Z0-9_.-]*$
Explanation:
^ is the beginning of the line anchor
$ is the end of the line anchor
[...] is a character class definition
* is "zero-or-more" repetition
Note that the literal dash - is the last character in the character class definition, otherwise it has a different mean...
When should I use GET or POST method? What's the difference between them?
What's the difference when using GET or POST method? Which one is more secure? What are (dis)advantages of each of them?
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java.lang.IllegalStateException: Cannot (forward | sendRedirect | create session) after response has
...mon misunderstanding among starters is that they think that the call of a forward(), sendRedirect(), or sendError() would magically exit and "jump" out of the method block, hereby ignoring the remnant of the code. For example:
protected void doXxx() {
if (someCondition) {
sendRedirect();...
Looking to understand the iOS UIViewController lifecycle
Could you explain me the correct manner to manage the UIViewController lifecycle?
11 Answers
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Regular vs Context Free Grammars
I'm studying for my computing languages test, and there's one idea I'm having problems wrapping my head around.
8 Answe...
What do “branch”, “tag” and “trunk” mean in Subversion repositories?
I've seen these words a lot around Subversion (and I guess general repository) discussions.
I have been using SVN for my projects for the last few years, but I've never grasped the complete concept of these directories.
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Why are these constructs using pre and post-increment undefined behavior?
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C has the concept of undefined behavior, i.e. some language constructs are syntactically valid but you can't predict the behavior when the code is run.
As far as I know, the standard doesn't explicitly say why the concept of undefined behavior exists. In my min...