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How do you do natural logs (e.g. “ln()”) with numpy in Python?
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Correct, np.log(x) is the Natural Log (base e log) of x.
For other bases, remember this law of logs: log-b(x) = log-k(x) / log-k(b) where log-b is the log in some arbitrary base b, and log-k is the log in base k, e.g.
here k = e
l = np.l...
Create Directory When Writing To File In Node.js
...d found a little problem. I've got a script which resides in a directory called data . I want the script to write some data to a file in a subdirectory within the data subdirectory. However I am getting the following error:
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How to create a private class method?
... answered Feb 10 '11 at 3:26
tjwallacetjwallace
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SQL - Rounding off to 2 decimal places
...the round v cast on its own. The convert to numeric doesn't do rounding in all engines so if the calculated number was 10.809 you would get 10.80 rather than the 10.81 the question required.
– u07ch
Aug 26 '14 at 7:47
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Padding is invalid and cannot be removed?
...t are the same. The padding method even if not explicitly set should still allow for proper decryption/encryption (if not set they will be the same). However if you for some reason are using a different set of keys for decryption than used for encryption you will get this error:
Padding is inval...
Write to .txt file?
How can I write a little piece of text into a .txt file?
I've been Googling for over 3-4 hours, but can't find out how to do it.
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How to know/change current directory in Python shell?
...now how to change.
edit
Under Windows:
set PYTHONPATH=%PYTHONPATH%;C:\My_python_lib
(taken from http://docs.python.org/using/windows.html)
edit 2
... and even better: use virtualenv and virtualenv_wrapper, this will allow you to create a development environment where you can add module paths ...
Difference between 'struct' and 'typedef struct' in C++?
...struct Foo x;
Any time you want to refer to a Foo, you'd always have to call it a struct Foo. This gets annoying fast, so you can add a typedef:
struct Foo { ... };
typedef struct Foo Foo;
Now struct Foo (in the tag namespace) and just plain Foo (in the ordinary identifier namespace) both refe...
Why doesn't 'ref' and 'out' support polymorphism?
...nswer as the basis for this blog entry:
Why do ref and out parameters not allow type variation?
See the blog page for more commentary on this issue. Thanks for the great question.
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Let's suppose you have classes Animal, Mammal, Reptile, Giraffe, Turtle and Tiger, with the obvious s...
String.IsNullOrWhiteSpace in LINQ Expression
...INQ provider to deliver an optimized query. During this transformation not all C# statements are supported, as it either is not possible to translate them to a back-end specific query (e.g. SQL) or because the implementer did not foresee the need for the statement.
In contrast IEnumerable<T>...