大约有 40,000 项符合查询结果（耗时：0.0417秒） [XML]
C# switch statement limitations - why?
...le use if they aren't:
case 10: blah; break;
case 200: blah; break;
case 3000: blah; break;
(You'd need a table ~3000 entries in size, with only 3 slots used)
With non-adjacent expressions, the compiler may start to perform linear if-else-if-else checks.
With larger non- adjacent expression set...
Pandas: create two new columns in a dataframe with values calculated from a pre-existing column
... also much faster on larger DataFrames
df = pd.DataFrame({'a': [1,2,3] * 100000, 'b': [2,3,4] * 100000})
DataFrame created with 300,000 rows
%timeit df["A1"], df["A2"] = calculate(df['a'])
2.65 ms ± 92.4 µs per loop (mean ± std. dev. of 7 runs, 100 loops each)
%timeit df["A1"], df["A2"] = zi...
What can MATLAB do that R cannot do? [closed]
...operations).
R has statistical functionality hard to find elsewhere (>2000 Packages on CRAN), and lots of statisticians use it. On the other hand, MATLAB has lots of (expensive) toolboxes for engineering applications like
image processing/image acquisition,
filter design,
fuzzy logic/fuzzy con...
ActiveRecord: size vs count
...a query at all.
Consider one example:
in my database, one customer has 20,000 customer activities and I try to count the number of records of customer activities of that customer with each of count, length and size method. here below the benchmark report of all these methods.
user ...
Why is it impossible to override a getter-only property and add a setter? [closed]
...GishuGishu
124k4545 gold badges214214 silver badges294294 bronze badges
94
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Send string to stdin
...y
xxd -r -p <<BINARY | iconv -f UCS-4BE -t UTF-8 | /my/bash/script
0000 79c1 0000 306f 0000 3061 0000 3093 0000 3077 0000 3093 0000 304b 0000 3093 0000 3077 0000 3093 0000 306a 0000 8a71 0000 306b 0000 30ca 0000 30f3 0000 30bb
0000 30f3 0000 30b9 0000 3092 0000 7ffb 0000 8a33 0000 3059 0000 ...
“On-line” (iterator) algorithms for estimating statistical median, mode, skewness, kurtosis?
...om your set (e.g. that you don't introduce a bias by picking the first 100'000 values). The same approach can also be used for estimating mode and median for the normal case (for both the sample mean is an estimator).
Further comments
All the algorithms above can be run in parallel (including many...
Correct way to use StringBuilder in SQL
...
@Vanathi: Glad that helped. Yeah, if it's going to be 6,000 characters, telling StringBuilder that in advance will save about eight memory reallocations (assuming the initial string was about 10 characters, the SB would have been 26 to start with, then doubled to 52, then 104, 208...
Android: textColor of disabled button in selector not showing?
..._enabled="false" android:color="#9D9FA2" />
<item android:color="#000"/>
</selector>
In your style.xml, put a reference to that text_color.xml file as follows:
<style name="buttonStyle" parent="@android:style/Widget.Button">
<item name="android:textStyle">bold</i...
Is String.Format as efficient as StringBuilder
...
I ran some quick performance benchmarks, and for 100,000 operations averaged over 10 runs, the first method (String Builder) takes almost half the time of the second (String Format).
So, if this is infrequent, it doesn't matter. But if it is a common operation, then you may wa...