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How to use glOrtho() in OpenGL?
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151
Have a look at this picture: Graphical Projections
The glOrtho command produces an "Oblique"...
SQL Logic Operator Precedence: And and Or
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And has precedence over Or, so, even if a <=> a1 Or a2
Where a And b
is not the same as
Where a1 Or a2 And b,
because that would be Executed as
Where a1 Or (a2 And b)
and what you want, to make them the same, is the following (using parentheses to override rule...
Dictionaries and default values
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edited Jan 23 '19 at 5:30
Solomon Ucko
2,42022 gold badges1212 silver badges2727 bronze badges
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Version number comparison in Python
...ite a cmp -like function which compares two version numbers and returns -1 , 0 , or 1 based on their compared valuses.
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Common MySQL fields and their appropriate data types
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71
Someone's going to post a much better answer than this, but just wanted to make the point that p...
List All Redis Databases
...atabases is fixed, and set in the configuration file. By default, you have 16 databases. Each database is identified by a number (not a name).
You can use the following command to know the number of databases:
CONFIG GET databases
1) "databases"
2) "16"
You can use the following command to list ...
Does the ternary operator exist in R?
... returns the latest evaluation, if-else is equivalent to ?:.
> a <- 1
> x <- if(a==1) 1 else 2
> x
[1] 1
> x <- if(a==2) 1 else 2
> x
[1] 2
The power of R is vectorization. The vectorization of the ternary operator is ifelse:
> a <- c(1, 2, 1)
> x <- ifelse(a=...
Pandas dataframe get first row of each group
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>>> df.groupby('id').first()
value
id
1 first
2 first
3 first
4 second
5 first
6 first
7 fourth
If you need id as column:
>>> df.groupby('id').first().reset_index()
id value
0 1 first
1 2 first
2 3 first
3 4 seco...
Convert tuple to list and back
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answered May 6 '14 at 14:27
KhonixKhonix
3,32311 gold badge1111 silver badges1515 bronze badges
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