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git ignore vim temporary files
...t is the correct way to make git ignore temporary files produced by vim in all directories (either globally across the system or locally for a single project)?
...
SQLAlchemy: cascade delete
...use that is where you defined your relationship (it doesn't care that you called it "Child" of course).
If you define the relationship on the Parent class instead, it will work:
children = relationship("Child", cascade="all,delete", backref="parent")
(note "Child" as a string: this is allowed wh...
Should import statements always be at the top of a module?
...t that's only paid once.
Putting the imports within a function will cause calls to that function to take longer.
So if you care about efficiency, put the imports at the top. Only move them into a function if your profiling shows that would help (you did profile to see where best to improve perform...
Nested or Inner Class in PHP
...There are several compelling reasons for using them:
It is a way of logically grouping classes that are only used in one place.
If a class is useful to only one other class, then it is logical to
relate and embed it in that class and keep the two together.
It increases encapsulation.
...
How do I change the working directory in Python?
...If the exception is thrown, do not perform any recursive operations, especially destructive ones. They will operate on the old path and not the new one.
Return to your old directory when you're done. This can be done in an exception-safe manner by wrapping your chdir call in a context manager, lik...
How do I spool to a CSV formatted file using SQLPLUS?
...tion on IDs)
spool myfile.csv
select table_name, tablespace_name
from all_tables
where owner = 'SYS'
and tablespace_name is not null;
Output will be like:
TABLE_PRIVILEGE_MAP ,SYSTEM
SYSTEM_PRIVILEGE_MAP ,SYSTEM
...
Python __str__ and lists
In Java, if I call List.toString(), it will automatically call the toString() method on each object inside the List. For example, if my list contains objects o1, o2, and o3, list.toString() would look something like this:
...
python: how to identify if a variable is an array or a scalar
I have a function that takes the argument NBins . I want to make a call to this function with a scalar 50 or an array [0, 10, 20, 30] . How can I identify within the function, what the length of NBins is? or said differently, if it is a scalar or a vector?
...
How to use timeit module
...
The way timeit works is to run setup code once and then make repeated calls to a series of statements. So, if you want to test sorting, some care is required so that one pass at an in-place sort doesn't affect the next pass with already sorted data (that, of course, would make the Timsort reall...
Underscore prefix for property and method names in JavaScript
...
Welcome to 2019!
It appears a proposal to extend class syntax to allow for # prefixed variable to be private was accepted. Chrome 74 ships with this support.
_ prefixed variable names are considered private by convention but are still public.
This syntax tries to be both terse and int...