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How does deriving work in Haskell?
Algebraic Data Types (ADTs) in Haskell can automatically become instances of some typeclasse s (like Show , Eq ) by deriving from them.
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How do I check if there are duplicates in a flat list?
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Use set() to remove duplicates if all values are hashable:
>>> your_list = ['one', 'two', 'one']
>>> len(your_list) != len(set(your_list))
True
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Comparing strings with == which are declared final in Java
...nal and initialized with a compile-time constant expression (§15.28), is called a constant variable.
Also from JLS §15.28 - Constant Expression:
Compile-time constant expressions of type String are always "interned" so as to share unique instances, using the method String#intern().
This ...
Determine if 2 lists have the same elements, regardless of order? [duplicate]
... helper function. Note that it will be quite slow (O(n²)) and should generally not be used outside of the esoteric case of unhashable and unsortable elements.
def equal_ignore_order(a, b):
""" Use only when elements are neither hashable nor sortable! """
unmatched = list(b)
for element...
Python, creating objects
... = ""
age = 0
major = ""
# The class "constructor" - It's actually an initializer
def __init__(self, name, age, major):
self.name = name
self.age = age
self.major = major
def make_student(name, age, major):
student = Student(name, age, major)
return...
In what areas might the use of F# be more appropriate than C#? [closed]
... sweet spot for the language within enterprise software, namely algorithmically complex analysis of large data sets. My experience has been a very positive one. In particular:
Units of measure The industry I work in is littered with units. The equations I implemented (often of a geometric nature) d...
Stop pip from failing on single package when installing with requirements.txt
I am installing packages from requirements.txt
6 Answers
6
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Access multiple elements of list knowing their index
...3, 8, 5, 6])
b = [1, 2, 5]
print(list(a[b]))
# Result:
[1, 5, 5]
But really, your current solution is fine. It's probably the neatest out of all of them.
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Regular expression to find URLs within a string
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It's 2017, and unicode domain names are all over the place. \w may not match international symbols (depends on regex engine), the range is needed instead: a-zA-Z0-9\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF.
– Michael Antipin
Aug...
What is your favorite C programming trick? [closed]
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C99 offers some really cool stuff using anonymous arrays:
Removing pointless variables
{
int yes=1;
setsockopt(yourSocket, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int));
}
becomes
setsockopt(yourSocket, SOL_SOCKET, SO_REUSEADDR...