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Modifying a subset of rows in a pandas dataframe
..., use NumPy's where function.
Setup
Create a two-column DataFrame with 100,000 rows with some zeros.
df = pd.DataFrame(np.random.randint(0,3, (100000,2)), columns=list('ab'))
Fast solution with numpy.where
df['b'] = np.where(df.a.values == 0, np.nan, df.b.values)
Timings
%timeit df['b'] = np.where...
Android Studio Editor Font Sizing
...his question has almost 31k views. The UI was so bad that they confused 31,000 programmers!
– localhost
Feb 12 '16 at 11:28
...
How can I convert a zero-terminated byte array to string?
...= max { return max }
mid := (min + max) / 2
if b[mid] == '\000' {
max = mid
} else {
min = mid
}
}
return len(b)
}
func main() {
b := []byte{1, 2, 3, 0, 0, 0}
fmt.Println(FirstZero(b))
}
It may be faster just to naively scan t...
How to get the data-id attribute?
...so doesn't change the value's representation. For example, "1E02" and "100.000" are equivalent as numbers (numeric value 100) but converting them would alter their representation so they are left as strings. "
– Wesley Murch
Mar 29 '14 at 4:29
...
T-SQL: Deleting all duplicate rows but keeping one [duplicate]
... Using this format I got the following error, any ideas? "ERROR 1093 (HY000): You can't specify target table 'Table' for update in FROM clause"
– M1ke
Aug 23 '13 at 11:24
...
How to get last key in an array?
...y(array_slice($array, -1, 1, true));
As the tests say, on an array with 500000 elements, it is almost 7x faster!
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Change Name of Import in Java, or import two classes with the same name
...hese situations would occur less frequently in java (where you can have 10.000+ classes) than in other languages (where you usually have less classes) which do support this "sugar" syntax.
– Alain Pannetier
May 21 '17 at 18:29
...
Who is listening on a given TCP port on Mac OS X?
...grep $PORT - I made an alias with this command
– alyn000r
Aug 1 '16 at 20:55
I would suggest adding "| grep $PORT" or...
Can unit testing be successfully added into an existing production project? If so, how and is it wor
...500+ or so tests yielding about 33 % code coverage in a code base with 230 000 + production LOC (real time financial Win-Forms application). That may sound low, but the result was a significant improvement in code quality and defect rate - plus improved morale and profitability.
It can be done when...
JS: iterating over result of getElementsByClassName using Array.forEach
...compared to other more intensive tasks like modifying DOM. If I execute 60,000 of these in 1 millisecond, I'm pretty sure it won't be an issue for any reasonable usage :)
– icl7126
Jul 31 '19 at 13:13
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