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Performance of foreach, array_map with lambda and array_map with static function
...W, I just did the benchmark since poster didn't do it. Running on PHP 5.3.10 + XDebug.
UPDATE 2015-01-22 compare with mcfedr's answer below for additional results without XDebug and a more recent PHP version.
function lap($func) {
$t0 = microtime(1);
$numbers = range(0, 1000000);
$ret = $f...
How do I include negative decimal numbers in this regular expression?
...e with positive values, but I want it to also allow negative values e.g. -10, -125.5 etc.
14 Answers
...
Getting the array length of a 2D array in Java
... };
System.out.println(foo.length); //2
System.out.println(foo[0].length); //3
System.out.println(foo[1].length); //4
}
Column lengths differ per row. If you're backing some data by a fixed size 2D array, then provide getters to the fixed values in a wrapper class.
...
What's the difference between a single precision and double precision floating point operation?
...entation requires a 32 bit word, which may be represented as numbered from 0 to 31, left to right.
The first bit is the sign bit, S,
the next eight bits are the exponent bits, 'E', and
the final 23 bits are the fraction 'F':
S EEEEEEEE FFFFFFFFFFFFFFFFFFFFFFF
0 1 8 9 3...
How can I convert a Unix timestamp to DateTime and vice versa?
...
1059
Here's what you need:
public static DateTime UnixTimeStampToDateTime( double unixTimeStamp )
...
Validate that a string is a positive integer
...
302
Two answers for you:
Based on parsing
Regular expression
Note that in both cases, I've inte...
Filter rows which contain a certain string
...
mpg cyl disp hp drat wt qsec vs am gear carb type
1 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4 Mazda RX4
2 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4 Mazda RX4 Wag
3 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1 Toyota Corolla
4 21.5 4 120.1 97 3....
Bin size in Matplotlib (Histogram)
... boundaries. They can be unequally distributed, too:
plt.hist(data, bins=[0, 10, 20, 30, 40, 50, 100])
If you just want them equally distributed, you can simply use range:
plt.hist(data, bins=range(min(data), max(data) + binwidth, binwidth))
Added to original answer
The above line works for...
How do I calculate percentiles with python/numpy?
...y too.
import numpy as np
a = np.array([1,2,3,4,5])
p = np.percentile(a, 50) # return 50th percentile, e.g median.
print p
3.0
This ticket leads me to believe they won't be integrating percentile() into numpy anytime soon.
...
Javascript calculate the day of the year (1 - 366)
... edit:
var now = new Date();
var start = new Date(now.getFullYear(), 0, 0);
var diff = now - start;
var oneDay = 1000 * 60 * 60 * 24;
var day = Math.floor(diff / oneDay);
console.log('Day of year: ' + day);
Edit: The code above will fail when now is a date in between march 26th and ...