I would like to filter out cnts with small area. But I got the an error. What is the proper way to use filter? code error Answer The filter function returns a generator but the drawContours function expects a list. To fix this, use the list command. Another solution is to use a list comprehension to build the list, like
Tag: functional-programming
pandas assign across multiple columns functionally
Is there a way, in pandas, to apply a function to some chosen columns, while strictly keeping a functional pipeline (no border effects,no assignation before the result, the result of the function only depends of its arguments, and I don’t want to drop the other columns). Ie, what is the equivalent of across in R ? In R, I would
Why can’t I assign lambda to the variable using ternary operator
When I assign anonymous function to the variable using ternary operator with the true condition, I can call the variable as a normal function. But when the condition is false and the function to be assigned is after the word else, I get something like this. I have no idea what mechanisms stand behind such a weird behaviour. Is there
Guard clause on lists using only functional programming
The problem I am facing is that, given a list and a guard condition, I must verify if every element in the list passes the guard condition. If even one of the elements fails the guard check, then the function should return false. If all of them pass the guard check, then the function should return true. The restriction on
Is there a Python equivalent for Scala’s Option or Either?
I really enjoy using the Option and Either monads in Scala. Are there any equivalent for these things in Python? If there aren’t, then what is the pythonic way of handling errors or “absence of value” without throwing exceptions? Answer The pythonic way for a function to say “I am not defined at this point” is to raise an exception.
Merge of lazy streams (using generators) in Python
I’m playing with functional capacities of Python 3 and I tried to implement classical algorithm for calculating Hamming numbers. That’s the numbers which have as prime factors only 2, 3 or 5. First Hamming numbers are 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 18, 20 and so on. My implementation is the following: The problem it that
How can I get a flat result from a list comprehension instead of a nested list?
I have a list A, and a function f which takes an item of A and returns a list. I can use a list comprehension to convert everything in A like [f(a) for a in A], but this returns a list of lists. Suppose my input is [a1,a2,a3], resulting in [[b11,b12],[b21,b22],[b31,b32]]. How can I get the flattened list [b11,b12,b21,b22,b31,b32] instead?