大约有 30,000 项符合查询结果(耗时:0.0422秒) [XML]
Android Get Current timestamp?
I want to get the current timestamp like that : 1320917972
12 Answers
12
...
Saving timestamp in mysql table using php
I have a field in a MySQL table which has a timestamp data type. I am saving data into that table. But when I pass the timestamp ( 1299762201428 ) to the record, it automatically saves the value 0000-00-00 00:00:00 into that table.
...
Create an index on a huge MySQL production table without table locking
...(and a few other things).
Test Script:
(
for n in {1..50}; do
#(time mysql -uroot -e 'select * from website_development.users where id = 41225\G'>/dev/null) 2>&1 | grep real;
(time mysql -uroot -e 'update website_development.users set bio="" where id = 41225\G'>/dev/null...
How to select rows from a DataFrame based on column values?
...2
7 foo three 7 14
Note, however, that if you wish to do this many times, it is more efficient to
make an index first, and then use df.loc:
df = df.set_index(['B'])
print(df.loc['one'])
yields
A C D
B
one foo 0 0
one bar 1 2
one foo 6 12
or, to includ...
Pandas aggregate count distinct
...ms much faster, tested here on ~21M rows dataframe, then grouped to ~2M
%time _=g.agg({"id": lambda x: x.nunique()})
CPU times: user 3min 3s, sys: 2.94 s, total: 3min 6s
Wall time: 3min 20s
%time _=g.agg({"id": pd.Series.nunique})
CPU times: user 3min 2s, sys: 2.44 s, total: 3min 4s
Wall time: 3m...
Memoization in Haskell?
...his very efficiently by making a structure that we can index in sub-linear time.
But first,
{-# LANGUAGE BangPatterns #-}
import Data.Function (fix)
Let's define f, but make it use 'open recursion' rather than call itself directly.
f :: (Int -> Int) -> Int -> Int
f mf 0 = 0
f mf n = m...
How do I get current date/time on the Windows command line in a suitable format for usage in a file/
...te /t') do (set mydate=%%c-%%a-%%b)
For /f "tokens=1-2 delims=/:" %%a in ('time /t') do (set mytime=%%a%%b)
echo %mydate%_%mytime%
If you prefer the time in 24 hour/military format, you can replace the second FOR line with this:
For /f "tokens=1-2 delims=/:" %%a in ("%TIME%") do (set mytime=%%a%%...
Is “double hashing” a password less secure than just hashing it once?
...n essential part of secure password use.
Iterating the hash increases the time it takes for an attacker to try each password in their list of candidates. You can easily increase the time it takes to attack a password from hours to years.
Simple iteration is not enough
Merely chaining hash output ...
Converting timestamp to time ago in PHP e.g 1 day ago, 2 days ago…
I am trying to convert a timestamp of the format 2009-09-12 20:57:19 and turn it into something like 3 minutes ago with PHP.
...
Algorithm for Determining Tic Tac Toe Game Over
...'s not about how many lines your solution consists of, it's about reducing time complexity of the algorithm to check for a winner.
– Shady
Feb 13 '15 at 11:00
...
