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Regular expression for floating point numbers
...source code.
– pkeller
Nov 9 '17 at 11:56
1
Can the regex [+-]?((?=\.?\d)\d*\.?\d*) be used to av...
How to generate keyboard events in Python?
... : 0x79,
'pgdn' : 0x79,
'f1' : 0x7A,
'left' : 0x7B,
'right' : 0x7C,
'down' : 0x7D,
'up' : 0x7E
}
share
...
Lambda expression to convert array/List of String to array/List of Integers
...collect(Collectors.toList());
6 (bonus) Convert int[] to String[]
int[] a2 = {7, 8, 9};
String[] r6 = Arrays.stream(a2).mapToObj(Integer::toString).toArray(String[]::new);
Lots more variations are possible of course.
Also see Ideone version of these examples. Can click fork and then run to run...
SQL JOIN and different types of JOINs
...1.4: INNER-JOIN with SELF-JOIN
Select *
FROM Table1 A1 INNER JOIN Table1 A2 On A1.Pk = A2.Fk;
2.1: OUTER JOIN (full outer join)
Select *
FROM Table1 A FULL OUTER JOIN Table2 B On A.Pk = B.Fk;
2.2: LEFT JOIN
Select *
FROM Table1 A LEFT OUTER JOIN Table2 B On A.Pk = B.Fk;
2.3: RIGHT JOIN ...
Rename specific column(s) in pandas
...ata set and scenario). The test case below is to rename columns A M N Z to A2 M2 N2 Z2 in a dataframe with columns A to Z containing a million rows.
# Import required modules
import numpy as np
import pandas as pd
import timeit
# Create sample data
df = pd.DataFrame(np.random.randint(0,9999,size=(...
combinations between two lists?
...n:
>>> [name+number for name in 'ab' for number in '12']
['a1', 'a2', 'b1', 'b2']
>>> [name+number for name in 'abc' for number in '12']
['a1', 'a2', 'b1', 'b2', 'c1', 'c2']
share
|
...
Passing a 2D array to a C++ function
...rintf("%p\n", &arr);
}
int main()
{
double a1[10][10];
double a2[5][5];
printf("%p\n%p\n\n", &a1, &a2);
func(a1);
func(a2);
return 0;
}
The print statements are there to show that the arrays are getting passed by reference (by displaying the variables' addres...
Python strftime - date without leading 0?
...thon3.6, this can be expressed as an inline formatted string:
Python 3.6.0a2 (v3.6.0a2:378893423552, Jun 13 2016, 14:44:21)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import datetime
>>> dt = da...
John Carmack's Unusual Fast Inverse Square Root (Quake III)
...ynomial sum:
y = f(x)
can be exactly transformed into:
y = a0 + a1*x + a2*(x^2) + a3*(x^3) + a4*(x^4) + ...
Where a0, a1, a2,... are constants. The problem is that for many functions, like square root, for exact value this sum has infinite number of members, it does not end at some x^n. But, i...
Can the Unix list command 'ls' output numerical chmod permissions?
...you don't, * can find most of them:
/usr/bin$ stat -c '%a %n' *
755 [
755 a2p
755 a2ps
755 aclocal
...
It handles sticky, suid and company out of the box:
$ stat -c '%a %n' /tmp /usr/bin/sudo
1777 /tmp
4755 /usr/bin/sudo
...