大约有 30,000 项符合查询结果（耗时：0.0309秒） [XML]
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.
...
Play a Sound with Python [duplicate]
...form == 'darwin': call(["afplay","sound.mp3"]) What's expensive is wasting time on all these malfunctioning sound libraries tbh. Substituting xdg-open for mpg123 will give afplay functionality on Linux
– Louis Maddox
Jul 9 '14 at 12:00
...
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
...
How can I convert bigint (UNIX timestamp) to datetime in SQL Server?
How can I convert UNIX timestamp (bigint) to DateTime in SQL Server?
15 Answers
15
...
What's the best way to send a signal to all members of a process group?
...ignals do not kill it)
sleep 2 # wait terminate process (more time if required)
kill -KILL -"$PGID" # kill -9 if it does not intercept signals (or buggy)
Limitation
As noticed by davide and Hubert Kario, when kill is invoked by a process belonging to the same tree, kill risks to ki...
how to create a file name with the current date & time in python?
...
While not using datetime, this solves your problem (answers your question) of getting a string with the current time and date format you specify:
import time
timestr = time.strftime("%Y%m%d-%H%M%S")
print timestr
yields:
20120515-155045
so...
Insert current date in datetime format mySQL
...
If you're looking to store the current time just use MYSQL's functions.
mysql_query("INSERT INTO `table` (`dateposted`) VALUES (now())");
If you need to use PHP to do it, the format it Y-m-d H:i:s so try
$date = date('Y-m-d H:i:s');
mysql_query("INSERT INTO `t...
What is dynamic programming? [closed]
...
Dynamic programming is a technique used to avoid computing multiple times the same subproblem in a recursive algorithm.
Let's take the simple example of the Fibonacci numbers: finding the n th Fibonacci number defined by
Fn = Fn-1 + Fn-2 and F0 = 0, F1 = 1
Recursion
The obvious way to...
How to sort a dataframe by multiple column(s)
...lyr
sort from taRifx
orderBy from doBy
sortData from Deducer
Most of the time you should use the dplyr or data.table solutions, unless having no-dependencies is important, in which case use base::order.
I recently added sort.data.frame to a CRAN package, making it class compatible as discussed ...