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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 ...
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:
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Iteration ng-repeat only X times in AngularJs
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David LinDavid Lin
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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...
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
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TypeScript sorting an array
I've been trying to figure out a very strange issue I ran into with typescript. It was treating an inline Boolean expression as whatever the first value's type was instead of the complete expression.
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Map implementation with duplicate keys
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You are searching for a multimap, and indeed both commons-collections and Guava have several implementations for that. Multimaps allow for multiple keys by maintaining a collection of values per key, i.e. you can put a single object into the map, but you retrieve a coll...
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...
How do I split a string with multiple separators in javascript?
...t a string with multiple separators in JavaScript? I'm trying to split on both commas and spaces but, AFAIK, JS's split function only supports one separator.
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Update multiple columns in SQL
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The "tiresome way" is standard SQL and how mainstream RDBMS do it.
With a 100+ columns, you mostly likely have a design problem... also, there are mitigating methods in client tools (eg generation UPDATE statements) or by using ORMs
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