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Is std::vector so much slower than plain arrays?
...t it's the general wisdom that std::vector is "implemented as an array," blah blah blah. Today I went down and tested it, and it seems to be not so:
...
JavaScript equivalent of jQuery's extend method
I have a function that takes a config object as an argument. Within the function, I also have default object. Each of those objects contains properties that essentially work as settings for the rest of the code within the function. In order to prevent having to specify all of the settings wit...
What's the fastest way to merge/join data.frames in R?
...uplicate keys. (continued after code)
DF1 = data.frame(a = c(1, 1, 2, 2), b = 1:4)
DF2 = data.frame(b = c(1, 2, 3, 3, 4), c = letters[1:5])
merge(DF1, DF2)
b a c
1 1 1 a
2 2 1 b
3 3 2 c
4 3 2 d
5 4 2 e
DF1$c = DF2$c[match(DF1$b, DF2$b)]
DF1$c
[1] a b c e
Levels: a b c d e
> DF1
...
How to override the copy/deepcopy operations for a Python object?
I understand the difference between copy vs. deepcopy in the copy module. I've used copy.copy and copy.deepcopy before successfully, but this is the first time I've actually gone about overloading the __copy__ and __deepcopy__ methods. I've already Googled around and looked through the ...
SQL set values of one column equal to values of another column in the same table
I have a table with two DATETIME columns.
5 Answers
5
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Difference between map, applymap and apply methods in Pandas
Can you tell me when to use these vectorization methods with basic examples?
10 Answers
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SQL - Update multiple records in one query
I have table - config .
Schema:
config_name | config_value
9 Answers
9
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Random string generation with upper case letters and digits
...g uppercase ASCII chars and digits:
>>> string.ascii_uppercase
'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
>>> string.digits
'0123456789'
>>> string.ascii_uppercase + string.digits
'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'
Then we use a list comprehension to create a list of 'n' elements...
How to chain scope queries with OR instead of AND?
...astname=?', 'John', 'Smith')
Right now, there isn't any other OR support by the new AR3 syntax (that is without using some 3rd party gem).
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How to scale down a range of numbers with a known min and max value
So I am trying to figure out how to take a range of numbers and scale the values down to fit a range. The reason for wanting to do this is that I am trying to draw ellipses in a java swing jpanel. I want the height and width of each ellipse to be in a range of say 1-30. I have methods that find t...