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How to reorder data.table columns (without copying)
...ta.table(a = 1:3, b = 3:1, c = runif(3))
x
# a b c
# [1,] 1 3 0.2880365
# [2,] 2 2 0.7785115
# [3,] 3 1 0.3297416
setcolorder(x, c("c", "b", "a"))
x
# c b a
# [1,] 0.2880365 3 1
# [2,] 0.7785115 2 2
# [3,] 0.3297416 1 3
From ?setcolorder:
In data.table parlance, all s...
Given an array of numbers, return array of products of all other numbers (no division)
...
260
An explanation of polygenelubricants method is:
The trick is to construct the arrays (in the c...
How do the PHP equality (== double equals) and identity (=== triple equals) comparison operators dif
...
640
Difference between == and ===
The difference between the loosely == equal operator and the stri...
Path to Powershell.exe (v 2.0)
Where is the Powershell (version 2.0) located? What is the path to Powershell.exe? I have Windows Server 2008 and Powershell installed. When I look at this folder:
...
Label points in geom_point
...our="green", label=Name))+
geom_point() +geom_text(aes(label=Name),hjust=0, vjust=0)
EDIT: Label only values above a certain threshold:
ggplot(nba, aes(x= MIN, y= PTS, colour="green", label=Name))+
geom_point() +
geom_text(aes(label=ifelse(PTS>24,as.character(Name),'')),hjust=0,vjust...
Assign pandas dataframe column dtypes
...
Since 0.17, you have to use the explicit conversions:
pd.to_datetime, pd.to_timedelta and pd.to_numeric
(As mentioned below, no more "magic", convert_objects has been deprecated in 0.17)
df = pd.DataFrame({'x': {0: 'a', 1: 'b'}...
WAMP error: Forbidden You don't have permission to access /phpmyadmin/ on this server
...Override all
Order Deny,Allow
Deny from all
Allow from 127.0.0.1
</Directory>
Modern versions of Apache 2.2 and up will look for a IPv6 loopback instead of a IPv4 loopback (your localhost).
The real problem is that wamp is binding to an IPv6 address. The fix:
just add ...
Random float number generation
...need to employ a more advanced method.
This will generate a number from 0.0 to 1.0, inclusive.
float r = static_cast <float> (rand()) / static_cast <float> (RAND_MAX);
This will generate a number from 0.0 to some arbitrary float, X:
float r2 = static_cast <float> (rand()) / ...
Parsing command-line arguments in C?
...
190
To my knowledge, the three most popular ways how to parse command line arguments in C are:
Get...
How do I get Month and Date of JavaScript in 2 digit format?
...
("0" + this.getDate()).slice(-2)
for the date, and similar:
("0" + (this.getMonth() + 1)).slice(-2)
for the month.
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