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Rank function in MySQL
... (SELECT @curRank := 0) r
ORDER BY age;
The (SELECT @curRank := 0) part allows the variable initialization without requiring a separate SET command.
Test case:
CREATE TABLE person (id int, first_name varchar(20), age int, gender char(1));
INSERT INTO person VALUES (1, 'Bob', 25, 'M');
INSERT I...
how to stop browser back button using javascript
...
There are numerous reasons why disabling the back button will not really work. Your best bet is to warn the user:
window.onbeforeunload = function() { return "Your work will be lost."; };
This page does list a number of ways you could try to disable the back button, but none are guaranteed...
What do 'real', 'user' and 'sys' mean in the output of time(1)?
... time; User and Sys refer to CPU time used only by the process.
Real is wall clock time - time from start to finish of the call. This is all elapsed time including time slices used by other processes and time the process spends blocked (for example if it is waiting for I/O to complete).
User is t...
Python memory leaks [closed]
... have a long-running script which, if let to run long enough, will consume all the memory on my system.
9 Answers
...
“Too many values to unpack” Exception
...nATupleWithThreeValues()
print a
print b
raises
Traceback (most recent call last):
File "c.py", line 3, in ?
a,b = returnATupleWithThreeValues()
ValueError: too many values to unpack
Now, the reason why this happens in your case, I don't know, but maybe this answer will point you in the r...
Avoid browser popup blockers
...m javascript that is not invoked by direct user action. That is, you can call window.open in response to a button click without getting hit by the popup blocker, but if you put the same code in a timer event it will be blocked. Depth of call chain is also a factor - some older browsers only look a...
How to put multiple statements in one line?
...pproximate what you want.
As for the try ... except thing: It would be totally useless without the except. try says "I want to run this code, but it might throw an exception". If you don't care about the exception, leave away the try. But as soon as you put it in, you're saying "I want to handle a ...
error: ‘uint16_t’ does not name a type - C/C++ - 清泛网 - 专注C/C++及内核技术
...ght notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHA...
Python logging: use milliseconds in time format
...d of a struct_time, then (at least with modern versions of Python) we can call ct.strftime and then we can use %f to format microseconds:
import logging
import datetime as dt
class MyFormatter(logging.Formatter):
converter=dt.datetime.fromtimestamp
def formatTime(self, record, datefmt=None...
What are the special dollar sign shell variables?
... $3, ... are the positional parameters.
"$@" is an array-like construct of all positional parameters, {$1, $2, $3 ...}.
"$*" is the IFS expansion of all positional parameters, $1 $2 $3 ....
$# is the number of positional parameters.
$- current options set for the shell.
$$ pid of the current shell (...