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What's the fastest way to merge/join data.frames in R?
... the precise computation can make a huge difference on which package is fastest. For example, we do a merge and an aggregate below. We see that the results are nearly reversed for the two. In the first example from fastest to slowest we get: data.table, plyr, merge and sqldf whereas in the second...
Why does typeof NaN return 'number'?
... or
greater than +1.
All these values may not be the same. A simple test for a NaN is to test value == value is false.
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Correctly determine if date string is a valid date in that format
...aken from this answer. Also on php.net. Originally written by Glavić.]
Test cases:
var_dump(validateDate('2013-13-01')); // false
var_dump(validateDate('20132-13-01')); // false
var_dump(validateDate('2013-11-32')); // false
var_dump(validateDate('2012-2-25')); // false
var_dump(validateDat...
What's the fastest way to loop through an array in JavaScript?
...
After performing this test with most modern browsers:
https://jsben.ch/wY5fo
Currently, the fastest form of loop (and in my opinion the most syntactically obvious).
A standard for-loop with length caching
var i = 0, len = myArray.length;
w...
Iterate over a list of files with spaces
...to perform multiple steps the loop version is easier.
EDIT: Here's a nice test script so you can get an idea of the difference between different attempts at solving this problem
#!/usr/bin/env bash
dir=/tmp/getlist.test/
mkdir -p "$dir"
cd "$dir"
touch 'file not starting foo' foo foobar ba...
Test whether a Ruby class is a subclass of another class
I would like to test whether a class inherits from another class, but there doesn't seem to exist a method for that.
2 Answ...
How to change app name per Gradle build type
...e non-release part, I see that a bit differently as one might want to also test for localization issues while allowing the "release" and "test" builds to coexist on the same device. In such a case both builds might end up with the same launcher label, probably causing some confusion. That is what I ...
What's a quick way to test to see a file exists?
...he directory's files, or I can try to open a specific file. What's the fastest way? I just need to know if the file is there or if it does not exist.
...
How to process SIGTERM signal gracefully?
...n, similar to if you were to Ctrl+C your program.
Example program signals-test.py:
#!/usr/bin/python
from time import sleep
import signal
import sys
def sigterm_handler(_signo, _stack_frame):
# Raises SystemExit(0):
sys.exit(0)
if sys.argv[1] == "handle_signal":
signal.signal(signa...
How do you set a default value for a MySQL Datetime column?
...ith DATETIME...
But you can do it with TIMESTAMP:
mysql> create table test (str varchar(32), ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP);
Query OK, 0 rows affected (0.00 sec)
mysql> desc test;
+-------+-------------+------+-----+-------------------+-------+
| Field | Type | Null | Key | ...