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How to “test” NoneType in python?
... I question a variable that is a NoneType? I need to use if method, for example
7 Answers
...
Applicatives compose, monads don't
... values. This really bites. Compare
miffy :: Monad m => m Bool -> m x -> m x -> m x
miffy mb mt mf = do
b <- mb
if b then mt else mf
which uses the result of some effect to decide between two computations (e.g. launching missiles and signing an armistice), whereas
iffy :: Appl...
Generate random password string with requirements in javascript
...
Forcing a fixed number of characters is a bad idea. It doesn't improve the quality of the password. Worse, it reduces the number of possible passwords, so that hacking by bruteforcing becomes easier.
To generate a random word consisting...
What is the rationale for all comparisons returning false for IEEE754 NaN values?
... are not real numbers, and floating-point arithmetic does not satisfy the axioms of real arithmetic. Trichotomy is not the only property of real arithmetic that does not hold for floats, nor even the most important. For example:
Addition is not associative.
The distributive law does not hold.
Th...
What's the difference between std::move and std::forward
... with "t" being template param is special, and adjusts "t" to be
(for example) "int &" or non-ref "int" so std::forward knows what to do. */
void forwarding( t && arg ) {
std::cout << "via std::forward: ";
overloaded( std::forward< t >( arg ) );
std::cout <...
Why do people say there is modulo bias when using a random number generator?
...am going to post one here which will hopefully help people understand why exactly there is "modulo bias" when using a random number generator, like rand() in C++.
...
Intelligent point label placement in R
...oblem:
I did this by hand in Preview (very basic PDF/image viewer on OS X) in just a few minutes. (Edit: The workflow was exactly what you'd expect: I saved the plot as a PDF from R, opened it in Preview and created textboxes with the desired labels (9pt Helvetica) and then just dragged them arou...
Learning Python from Ruby; Differences and Similarities
...es from the outer scope.
Python has list comprehensions, which are pretty expressive. For example, if you have a list of numbers, you can write
[x*x for x in values if x > 15]
to get a new list of the squares of all values greater than 15. In Ruby, you'd have to write the following:
values....
How to profile a bash shell script slow startup?
...like to begin a trace in any Bash script):
PS4='+ $(date "+%s.%N")\011 '
exec 3>&2 2>/tmp/bashstart.$$.log
set -x
add
set +x
exec 2>&3 3>&-
at the end of ~/.bashrc (or at the end of the section of any Bash script you'd like tracing to stop). The \011 is an octal tab cha...
How can I convert JSON to CSV?
......]
Here is my code to generate CSV from that:
import csv
import json
x = """[
{
"pk": 22,
"model": "auth.permission",
"fields": {
"codename": "add_logentry",
"name": "Can add log entry",
"content_type": 8
}
},
{
...