How to chain multiple columns with 'AND' addition Question: I want to extract news by keyword and hashtags. In the keyword and hashtags, I want to combine them into 1 to create sentences in the form of strings using python. Here’s the table I have : the desired output is like this "Gempa AND #gempa …
Mapping set operations in python Question: I have a very simple problem, but today, I confess I have trouble finding the solution: I want to use the ‘&’ operator on python sets, but I don’t know how many sets I will have to deal with. Is it possible to use a mapping with python to …
why defining only __lt__ makes > operation possible? Question: class Node: def __init__(self,a,b): self._a=a self._b=b def __lt__(self,other): return self._a<other._a a=Node(1,2) b=Node(0,4) print(a>b) The code above shows True. class Node: def __init__(self,a,b): self._a=a self._b=b def __lt__(self,other): return self._a<other._a def __eq__(self,other): return self._a==other._a a=Node(1,2) b=Node(0,4) print(a>=b) The code above shows TypeError: ‘<=’ not supported between instances of …
Python AND operator on two boolean lists – how? Question: I have two boolean lists, e.g., x=[True,True,False,False] y=[True,False,True,False] I want to AND these lists together, with the expected output: xy=[True,False,False,False] I thought that expression x and y would work, but came to discover that it does not: in fact, (x and y) != (y and …
New operators in Python Question: We can define intrinsic operators of Python as stated here. Just for curiosity, can we define new operators like $ or ***? (If so, then we can define ternary condition operators or rotate operators.) Asked By: hola || Source Answers: No, you can’t define new operators in Python. Answered By: …
How do operator.itemgetter() and sort() work? Question: I have the following code: # initialize a = [] # create the table (name, age, job) a.append(["Nick", 30, "Doctor"]) a.append(["John", 8, "Student"]) a.append(["Paul", 22, "Car Dealer"]) a.append(["Mark", 66, "Retired"]) # sort the table by age import operator a.sort(key=operator.itemgetter(1)) # print the table print(a) It creates a 4×3 …
Python's Logical Operator AND Question: I’m a little confused with the results I’m getting with the logical operators in Python. I’m a beginner and studying with the use of a few books, but they don’t explain in as much detail as I’d like. here is my own code: five = 5 two = 2 print …
How efficient/fast is Python's 'in'? (Time Complexity wise) Question: In Python, what is the efficiency of the in keyword, such as in: a = [1, 2, 3] if 4 in a: … Asked By: John || Source Answers: The complexity for lists is: O(n) For sets it is: O(1) http://wiki.python.org/moin/TimeComplexity Answered By: Eduardo It depends …
Set "in" operator: uses equality or identity? Question: class A(object): def __cmp__(self): print ‘__cmp__’ return object.__cmp__(self) def __eq__(self, rhs): print ‘__eq__’ return True a1 = A() a2 = A() print a1 in set([a1]) print a1 in set([a2]) Why does first line prints True, but second prints False? And neither enters operator eq? I am using …
Python: multiplication override Question: So, I’ve got a custom class that has a __mul__ function which works with ints. However, in my program (in libraries), it’s getting called the other way around, i.e., 2 * x where x is of my class. Is there a way I can have it use my __mul__ function for …
