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Java 8 Streams - collect vs reduce
...two different approaches:
If we wanted to take a stream of strings and concatenate them into a
single long string, we could achieve this with ordinary reduction:
String concatenated = strings.reduce("", String::concat)
We would get the desired result, and it would even work in parall...
How to find and return a duplicate value in array
... test_array(nelements, ndups)
arr = CAPS[0, nelements-ndups]
arr = arr.concat(arr[0,ndups]).shuffle
end
and a method to run the benchmarks for different test arrays:
require 'fruity'
def benchmark(nelements, ndups)
arr = test_array nelements, ndups
puts "\n#{ndups} duplicates\n"
co...
Select by partial string from a pandas DataFrame
...
Performance wise, regex search is slower than substring search:
df2 = pd.concat([df1] * 1000, ignore_index=True)
%timeit df2[df2['col'].str.contains('foo')]
%timeit df2[df2['col'].str.contains('foo', regex=False)]
6.31 ms ± 126 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
2.8 ms ...
Split (explode) pandas dataframe string entry to separate rows
...
How about something like this:
In [55]: pd.concat([Series(row['var2'], row['var1'].split(','))
for _, row in a.iterrows()]).reset_index()
Out[55]:
index 0
0 a 1
1 b 1
2 c 1
3 d 2
4 e 2
5 f 2
Then yo...
Fastest way to flatten / un-flatten nested JSON objects
... Object.keys(obj).forEach(key => {
this.flatten(obj[key], prefix.concat(key), current)
})
} else {
current[prefix.join('.')] = obj
}
return current
}
Features and/or caveats
It only accepts JSON objects. So if you pass something like {a: () => {}} you might not get wh...
Quickest way to convert a base 10 number to any base in .NET?
...ike that (note that this surely can be made faster by replacing the string concatenation):
class Program
{
static void Main(string[] args)
{
// convert to binary
string binary = IntToString(42, new char[] { '0', '1' });
// convert to hexadecimal
string hex =...
Adding new column to existing DataFrame in Python pandas
... @Owlright From the question, it appears that the OP is simply concatenating the dataframes and ignoring the index. If this is the case, the the methods above will work. If one wishes to retain the index, then use something like df_new = pd.concat([df1, df2], axis=1), noting that ignore...
Simple insecure two-way data “obfuscation”?
...6];
this.random.NextBytes(vector);
var cryptogram = vector.Concat(this.Encrypt(this.encoder.GetBytes(unencrypted), vector));
return Convert.ToBase64String(cryptogram.ToArray());
}
public string Decrypt(string encrypted)
{
var cryptogram = Convert.FromBase...
What are good alternatives to SQL (the language)? [closed]
...uage today, I suspect join syntax would be different, functions like GROUP_CONCAT would have more regular syntax rather than sticking more keywords in the middle of the parentheses to control its behavior... create your own laundry list of inconsistencies and redundancies in SQL that you'd like/expe...
How do I control how Emacs makes backup files?
...Here is a configuration that IMHO works best:
(defvar --backup-directory (concat user-emacs-directory "backups"))
(if (not (file-exists-p --backup-directory))
(make-directory --backup-directory t))
(setq backup-directory-alist `(("." . ,--backup-directory)))
(setq make-backup-files t ...