大约有 40,000 项符合查询结果（耗时：0.0423秒） [XML]
String concatenation: concat() vs “+” operator
...then throwing it away when you create the final String. In practice memory allocation is surprisingly fast.
Update: As Pawel Adamski notes, performance has changed in more recent HotSpot. javac still produces exactly the same code, but the bytecode compiler cheats. Simple testing entirely fails bec...
How to add a progress bar to a shell script?
...}
done
If you already have a loop which does a lot of work, you can call the
following function at the beginning of each iteration to update the
spinner:
sp="/-\|"
sc=0
spin() {
printf "\b${sp:sc++:1}"
((sc==${#sp})) && sc=0
}
endspin() {
printf "\r%s\n" "$@"
}
until wor...
java get file size efficiently
...97.044
URL sum: 95534, per Iteration: 382.136
File must be caching the calls to the filesystem, while channels and URL have some overhead.
Code:
import java.io.*;
import java.net.*;
import java.util.*;
public enum FileSizeBench {
LENGTH {
@Override
public long getResult() ...
Best way to handle list.index(might-not-exist) in python?
...thonic solution is to use only try/except and not the -1 sentinel value at all. I.E. you should rewrite otherfunction. On the other hand, if it ain't broke, ...
– Andrew Jaffe
Jan 25 '10 at 15:49
...
std::vector performance regression when enabling C++11
I have found an interesting performance regression in a small C++ snippet, when I enable C++11:
1 Answer
...
How to use php serialize() and unserialize()
...
echo json_encode($array); How exactly you pass it depends on the circumstances. Don't get too hung up on that.
– deceze♦
Dec 27 '11 at 7:57
...
find -exec with multiple commands
...e? this is failing: find ./* -exec grep -v 'COLD,' {} \; -exec egrep -i "my_string" {} \;
– rajeev
Jan 22 '13 at 16:08
53
...
How to drop all tables in a SQL Server database?
...y tables.
I found that code that works and does everything you try (delete all tables from your database):
DECLARE @Sql NVARCHAR(500) DECLARE @Cursor CURSOR
SET @Cursor = CURSOR FAST_FORWARD FOR
SELECT DISTINCT sql = 'ALTER TABLE [' + tc2.TABLE_SCHEMA + '].[' + tc2.TABLE_NAME + '] DROP [' + rc1.C...
Visualizing branch topology in Git
...n on my own machine, and I find it difficult to maintain a mental model of all my branches and commits. I know I can do a git log to see the commit history from where I am, but is there a way to see the entire branch topography, something like these ASCII maps that seem to be used everywhere for e...
Where is Maven' settings.xml located on mac os?
...8:00)
Maven home: /usr/local/Cellar/maven/3.5.0/libexec
Java version: 1.8.0_121, vendor: Oracle Corporation
Java home: /Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/jre
Default locale: zh_CN, platform encoding: UTF-8
OS name: "mac os x", version: "10.11.5", arch: "x86_64", family:...