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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 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....
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:
...
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
>>>...
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
...
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...
How to take column-slices of dataframe in pandas
...
10 Answers
10
Active
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Delete first character of a string in Javascript
...ant to delete the first character of a string, if the first character is a 0. The 0 can be there more than once.
14 Answer...
Limit Decimal Places in Android EditText
...
120
More elegant way would be using a regular expression ( regex ) as follows:
public class Decimal...
Remove rows with duplicate indices (Pandas DataFrame and TimeSeries)
...
502
I would suggest using the duplicated method on the Pandas Index itself:
df3 = df3[~df3.index.du...