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Append value to empty vector in R?
...et.seed(21)
values <- sample(letters, 1e4, TRUE)
vector <- character(0)
# slow
system.time( for (i in 1:length(values)) vector[i] <- values[i] )
# user system elapsed
# 0.340 0.000 0.343
vector <- character(length(values))
# fast(er)
system.time( for (i in 1:length(values)) vec...
How to filter Pandas dataframe using 'in' and 'not in' like in SQL
...where)
As a worked example:
import pandas as pd
>>> df
country
0 US
1 UK
2 Germany
3 China
>>> countries_to_keep
['UK', 'China']
>>> df.country.isin(countries_to_keep)
0 False
1 True
2 False
3 True
Name: country, dtype: bool
>>>...
Modify SVG fill color when being served as Background-Image
... |
edited Dec 21 '18 at 0:15
David Neto
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answered ...
Is it correct to use JavaScript Array.sort() method for shuffling?
...
110
It's never been my favourite way of shuffling, partly because it is implementation-specific as y...
How do I find out if first character of a string is a number?
...
260
Character.isDigit(string.charAt(0))
Note that this will allow any Unicode digit, not just 0-9....
Tools for analyzing performance of a Haskell program
...oblem.
Run your program with +RTS -s
$ time ./A +RTS -s
./A +RTS -s
749700
9,961,432,992 bytes allocated in the heap
2,463,072 bytes copied during GC
29,200 bytes maximum residency (1 sample(s))
187,336 bytes maximum slop
**2 MB** total memory in use (0...
Where can I find a NuGet package for upgrading to System.Web.Http v5.0.0.0?
Just upgraded an ASP.NET MVC4 project to use Unity.WebApi version 5.0.0.0 and it requires System.Web.Http v 5.0.0.0 as per the following error:
...
Converting RGB to grayscale/intensity
...ic weights to channels R, G, and B ought to be applied. These weights are: 0.2989, 0.5870, 0.1140.
8 Answers
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Limit Decimal Places in Android EditText
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120
More elegant way would be using a regular expression ( regex ) as follows:
public class Decimal...
How do the PHP equality (== double equals) and identity (=== triple equals) comparison operators dif
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640
Difference between == and ===
The difference between the loosely == equal operator and the stri...