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What is PECS (Producer Extends Consumer Super)?
...f a programming language, a typing rule
covariant if it preserves the ordering of types (≤), which orders types from more specific to more generic;
contravariant if it reverses this ordering;
invariant or nonvariant if neither of these applies.
Covariance and contravariance
Read-only data...
How to get the input from the Tkinter Text Widget?
...ly issue with this is that it actually adds a newline to our input. So, in order to fix it we should change END to end-1c(Thanks Bryan Oakley) The -1c deletes 1 character, while -2c would mean delete two characters, and so on.
def retrieve_input():
input = self.myText_Box.get("1.0",'end-1c')
...
Comparing two dataframes and getting the differences
...hod, and exception is raised if differences found, even in columns/indices order.
If I got you right, you want not to find changes, but symmetric difference. For that, one approach might be concatenate dataframes:
>>> df = pd.concat([df1, df2])
>>> df = df.reset_index(drop=True)
...
Change font color for comments in vim
...t was because that line came before the line syntax on, once i swapped the order, it worked fine..
– guskenny83
Jun 23 '16 at 3:51
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show 3 ...
How do I link a JavaScript file to a HTML file?
... HTML document, ideally inside the which points to your javascript files. Order of the script tags are important. Load the jQuery before your script files if you want to use jQuery from your script.
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min...
How can I add a column that doesn't allow nulls in a Postgresql database?
...row. Not sure how Postgres locks up a table when doing this. Or, if column order matters, you can't just add a column with the ALTER command.
– alphadogg
Feb 5 '09 at 14:31
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Which concurrent Queue implementation should I use in Java?
...conds).
Fairness means that the Lock implementation will keep the threads ordered. Meaning if Thread A enters and then Thread B enters, Thread A will get the lock first. With no fairness, it is undefined really what happens. It will most likely be the next thread that gets scheduled.
As for whi...
Regex select all text between tags
...means "OR".
+? Plus character states to select one or more of the above - order does not matter. Question mark changes the default behavior from 'greedy' to 'ungreedy'.
(?=(</pre>)) Selection have to be appended by the </pre> tag
Depending on your use case you might need to add some...
How to declare an array in Python?
...*The default built-in Python type is called a list, not an array. It is an ordered container of arbitrary length that can hold a heterogenous collection of objects (their types do not matter and can be freely mixed). This should not be confused with the array module, which offers a type closer to th...
dynamic_cast and static_cast in C++
...hic classes. In fact, in certian cases the classes must be polymorphic in order for the cast to be legal.
Casts can go in one of two directions: from base to derived (B2D) or from derived to base (D2B). It's simple enough to see how D2B casts would work at runtime. Either ptr was derived from T...