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Python syntax for “if a or b or c but not all of them”
...ve either zero or three command line arguments. (Either it runs on default behavior or needs all three values specified.)
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What is the best way to concatenate two vectors?
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AB.reserve( A.size() + B.size() ); // preallocate memory
AB.insert( AB.end(), A.begin(), A.end() );
AB.insert( AB.end(), B.begin(), B.end() );
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Insert an element at a specific index in a list and return the updated list
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l.insert(index, obj) doesn't actually return anything. It just updates the list.
As ATO said, you can do b = a[:index] + [obj] + a[index:].
However, another way is:
a = [1, 2, 4]
b = a[:]
b.insert(2, 3)
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Circular list iterator in Python
I need to iterate over a circular list, possibly many times, each time starting with the last visited item.
6 Answers
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What's a correct and good way to implement __hash__()?
... easy, correct way to implement __hash__() is to use a key tuple. It won't be as fast as a specialized hash, but if you need that then you should probably implement the type in C.
Here's an example of using a key for hash and equality:
class A:
def __key(self):
return (self.attr_a, sel...
String concatenation: concat() vs “+” operator
Assuming String a and b:
11 Answers
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Can we make unsigned byte in Java
I am trying to convert a signed byte in unsigned. The problem is the data I am receiving is unsigned and Java does not support unsigned byte, so when it reads the data it treats it as signed.
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Simple way to find if two different lists contain exactly the same elements?
...ind if two Lists contain exactly the same elements, in the standard Java libraries?
16 Answers
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Access lapply index names inside FUN
... pass it the names or indices of the vector instead of the vector itself.
But note that you can always pass in extra arguments to the function, so the following works:
x <- list(a=11,b=12,c=13) # Changed to list to address concerns in commments
lapply(seq_along(x), function(y, n, i) { paste(n[[...
Sorting an array of objects in Ruby by object attribute?
I have an array of objects in Ruby on Rails. I want to sort the array by an attribute of the object. Is it possible?
9 Answ...