大约有 37,000 项符合查询结果（耗时：0.0482秒） [XML]
How to append rows to an R data frame
...sive insight than system.time:
library(microbenchmark)
microbenchmark(f1(1000), f3(1000), f4(1000), times = 5)
# Unit: milliseconds
# expr min lq median uq max neval
# f1(1000) 1024.539618 1029.693877 1045.972666 1055.25931 1112.769176 5
# f3(1000) ...
How do I get time of a Python program's execution?
...s that your program takes at least a tenth of second to run.
Prints:
--- 0.764891862869 seconds ---
share
|
improve this answer
|
follow
|
...
Add unique constraint to combination of two columns
...g an exception (exceptions are expensive).
http://www.sqlperformance.com/2012/08/t-sql-queries/error-handling
http://www.mssqltips.com/sqlservertip/2632/checking-for-potential-constraint-violations-before-entering-sql-server-try-and-catch-logic/
If you want to prevent exceptions from bubbling up ...
Bash Script: count unique lines in file
...
306
You can use the uniq command to get counts of sorted repeated lines:
sort ips.txt | uniq -c
...
How do you convert a byte array to a hexadecimal string, and vice versa?
...
1402
Either:
public static string ByteArrayToString(byte[] ba)
{
StringBuilder hex = new StringBu...
Ruby: Merging variables in to a string
...
answered Feb 16 '09 at 21:42
Mike WoodhouseMike Woodhouse
47.6k1212 gold badges8585 silver badges123123 bronze badges
...
Cluster analysis in R: determine the optimal number of clusters
...
1024
If your question is how can I determine how many clusters are appropriate for a kmeans analysi...
Fancybox doesn't work with jQuery v1.9.0 [ f.browser is undefined / Cannot read property 'msie' ]
Fancybox breaks with the new jQuery v1.9.0.
4 Answers
4
...
How to do version numbers? [closed]
...e "unstable watchout" on there. So how would you go about versioning? Is 1.0 stable? Should the build date be in the version number? Tell me what you guys think!
...
How to find Unused Amazon EC2 Security groups
... |
edited Jul 1 at 20:15
Dherik
11.2k1010 gold badges7373 silver badges114114 bronze badges
answer...