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How to find all the subclasses of a class given its name?
I need a working approach of getting all classes that are inherited from a base class in Python.
10 Answers
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What are forward declarations in C++?
... wants to ensure you haven't made spelling mistakes or passed the wrong number of arguments to the function. So, it insists that it first sees a declaration of 'add' (or any other types, classes or functions) before it is used.
This really just allows the compiler to do a better job of validating t...
Does “\d” in regex mean a digit?
I found that in 123 , \d matches 1 and 3 but not 2 . I was wondering if \d matches a digit satisfying what kind of requirement? I am talking about Python style regex.
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What does the construct x = x || y mean?
I am debugging some JavaScript, and can't explain what this || does?
12 Answers
12
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Get operating system info
I recently started wondering about sites like http://thismachine.info/ that get the user's operating system info. I have not been able to find out how to do that with PHP, and wanted to try to figure it out.
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What is the purpose of setting a key in data.table?
I am using data.table and there are many functions which require me to set a key (e.g. X[Y] ). As such, I wish to understand what a key does in order to properly set keys in my data tables.
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Difference between HEAD and master
What is the difference between the HEAD and master in Git?
3 Answers
3
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What are bitwise operators?
...into it in either an academic or professional setting, so stuff like these bitwise operators really escapes me.
9 Answers
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LINQ - Left Join, Group By, and Count
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from p in context.ParentTable
join c in context.ChildTable on p.ParentId equals c.ChildParentId into j1
from j2 in j1.DefaultIfEmpty()
group j2 by p.ParentId into grouped
select new { ParentId = grouped.Key, Count = grouped.Count(t=>t.ChildId != nu...
Adding days to a date in Python
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The previous answers are correct but it's generally a better practice to do:
import datetime
Then you'll have, using datetime.timedelta:
date_1 = datetime.datetime.strptime(start_date, "%m/%d/%y")
end_date = date_1 + datetime.timedelta(days=10)
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