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Increment a value in Postgres
... I was trying to increment non-integer datatype and getting:ERROR: operator does not exist: character varying + integer LINE 2: SET total = total + 1 Solved by casting the value as integer like this SET total = total::int + 1
– Stew-au
...
Java: Get first item from a collection
...llection actually has contents. If it's empty the iterator might return an error, in which one has to check the collection size beforehand.
– spaceemotion
Nov 6 '15 at 17:05
24
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Measuring elapsed time with the Time module
...esolution.
Use of these can further eliminate rounding and floating-point errors, especially if you're measuring very short periods, or your application (or Windows machine) is long-running.
Resolution starts breaking down on perf_counter() after around 100 days. So for example after a year of upt...
Favorite Django Tips & Features?
...hing and replace hard coded urls. My only big complaint is that url tag errors kill the whole page while hard coded only messes up the individual link.
– ricree
Sep 4 '09 at 8:34
...
A weighted version of random.choice
...
This doesn't work with tuples etc ("ValueError: a must be 1-dimensional"), so in that case one can ask numpy to pick the index into the list, i.e. len(list_of_candidates), and then do list_of_candidates[draw]
– xjcl
Mar 17 '19 ...
Show a popup/message box from a Windows batch file
...y from the command prompt, but when I stick it in a batch file, I get this error: close() was unexpected at this time.
– eye_mew
Apr 23 '14 at 22:50
...
Highlight the difference between two strings in PHP
...ff matrix requires (m+1)*(n+1) elements. So you can run into out of memory errors if you try to diff long sequences. In this case diff larger chunks (eg. lines) first, then diff their contents in a second pass.
The algorithm can be improved if you trim the matching elements from the beginning and th...
Moment.js transform to date object
...ent.tz(dateStr, 'America/New_York').toString(); but then I started getting errors about feeding that string back into moment.
I tried the moment.tz(dateStr, 'America/New_York').toDate(); but then I lost timezone information which I needed.
The only solution that returned a usable date string with ...
MySQL - SELECT WHERE field IN (subquery) - Extremely slow why?
...ld must be in the select, because otherwise the having clause will give an error, but I'm not 100% sure
Never use IN with a subquery; this is notoriously slow.
Only ever use IN with a fixed list of values.
More tips
If you want to make queries faster,
don't do a SELECT * only select
the field...
Share variables between files in Node.js?
...onments/test.json
{
"mailerType": "Stub",
"mailerConfig": {
"error": false
}
}
(make a similar config for dev too)
To decide which config will be loaded make a main config file (this will be used all over the application)
// File: config/config.js
var _ = require('underscore');...