All Questions
19 questions
0
votes
1
answer
106
views
Is Python's map function evaluation lazy?
I've been solving LeetCode's 1331. Rank Transform of an Array challenge and came up with this one-line solution:
class Solution:
def arrayRankTransform(self):
return map({e: i for i, e in ...
- 218
0
votes
0
answers
143
views
POLARS: pycharm exited with following error code : -1073741819 (0xC0000005) while converting lazyframes to polars dataframe using lf.collect()
I have a piece of code which is performing some computations on top of lazy frames. I have the output stored in form of lazy frames in a dictionary. At the end, I am converting the outputs to pandas ...
2
votes
1
answer
493
views
Eager map in Python
In Python the map function is lazy, but most often I need an eager map.
For example, trying to slice a map object results in an error:
>>>> map(abs, [3, -1, -4, 1])[1:]
Traceback (most ...
- 363
1
vote
1
answer
231
views
Is there "non-lazy mode" or "strict mode" for "querysets" in Django?
When I use select_for_update() and update() of a queryset together as shown below:
# "store/views.py"
from django.db import transaction
from .models import Person
from django.http import ...
0
votes
1
answer
859
views
Python Hypothesis testing: Is there a way to avoid drawing a LazyStrategy?
If Python hypothesis strategies are too deeply nested, using draw will not create an actual example, but a LazyStrategy. This can be quite problematic at times because the resulting object behaves ...
- 7,060
0
votes
2
answers
243
views
lazy evaluation python data structure
I have the following code:
def get_data():
return {"a": 1, "b":2}
def main():
lazy_dic = lambda : get_data()
a_value = lazy_dic()["a"]
b_value = lazy_dic()...
- 1,895
4
votes
2
answers
2k
views
Lazy evaluation of dict values?
Suppose I have the following dict d={'a': heavy_expression1, 'b': heavy_expression2}.
How can I wrap the expressions, so that they are evaluated once they are accessed and after this no evaluation is ...
- 2,817
0
votes
0
answers
308
views
How to create lazy variable that is not a a property/attribute? [duplicate]
At this point, I have found several python implementations for lazily-evaluated property/attribute (also known as cached method), these include:
https://boltons.readthedocs.io/en/latest/index.html
...
- 3,898
7
votes
1
answer
651
views
Apply python lazy map for in-place functions?
Sometimes, I build up a thing by repeatedly applying map, and then having python perform the operations all at once.
For example, I could build up a list of lists of ranges like so:
foo = [256]*3
...
- 5,547
4
votes
1
answer
4k
views
Lazy evaluation when use lambda and list comprehension [duplicate]
Here is the example python code.
f_list = [lambda x : x ** i for i in range(5)]
[f_list[j](10) for j in range(5)]
I thought the output would be:
[1, 10, 100, 1000, 10000]
But I got this instead:
[...
user9821164
1
vote
2
answers
2k
views
method chain lazy execution in python [closed]
I have a chain of methods in my python program of the TestClass object like below:-
TestClass().method1(args).method2(args).method3(args)
I want to build a utility which will scan the above chain and ...
- 1,123
2
votes
0
answers
472
views
Python: How to access instance attributes in nested descriptors?
Example
Take the following example
class Leaf:
def __get__(self, instance, owner):
if instance is None:
return self
# TODO How to access Root.value here?
class ...
- 59
0
votes
1
answer
583
views
Python3, a lazy print
for my last project in Python3, i used a custom lazy generator to generate my data. Then use imap from a Pool (multiprocessing).
So at this point, not any computation have been made.
The next step is ...
- 333
16
votes
4
answers
15k
views
How to add a classmethod in Python dynamically
I'm using Python 3.
I know about the @classmethod decorator. Also, I know that classmethods can be called from instances.
class HappyClass(object):
@classmethod
def say_hello():
print(...
- 3,186
0
votes
2
answers
4k
views
Does range involve eager or lazy evaluation, in 2.x and 3.x? [duplicate]
I was looking at the range function and an online search shows that (EDIT: in 2.x) it's eagerly evaluated
>>> range(10)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
However when I try the code below in my ...
- 31.6k