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SQL UPDATE all values in a field with appended string CONCAT not working
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That's pretty much all you need:
mysql> select * from t;
+------+-------+
| id | data |
+------+-------+
| 1 | max |
| 2 | linda |
| 3 | sam |
| 4 | henry |
+------+-------+
4 rows in set (0.02 sec)
mysql> update t set data=concat(data, 'a');...
Razor comment syntax
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In visual studio, select some code/markup in your razor view and press Ctrl+K, Ctrl+C, and it'll comment the selection as described above.
– MrBoJangles
Feb 17 '11 at 18:12
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Is there a rule-of-thumb for how to divide a dataset into training and validation sets?
...o training and validation (again, 80/20 is a fair split).
Subsample random selections of your training data, train the classifier with this, and record the performance on the validation set
Try a series of runs with different amounts of training data: randomly sample 20% of it, say, 10 times and obs...
What is DOCTYPE?
...de), depending on the exact spelling of the DOCTYPE. You want to use it to select a browser mode that best suits your page.
Formally, in SGML and XML, a DOCTYPE declaration is a reference to a Document Type Definition (DTD), which specifies the formal syntax rules of the markup language. No browser...
How do you list all triggers in a MySQL database?
...w triggers;
or you can access the INFORMATION_SCHEMA table directly by:
select trigger_schema, trigger_name, action_statement
from information_schema.triggers
You can do this from version 5.0.10 onwards.
More information about the TRIGGERS table is here.
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Merge multiple lines (two blocks) in Vim
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You can certainly do all this with a single copy/paste (using block-mode selection), but I'm guessing that's not what you want.
If you want to do this with just Ex commands
:5,8del | let l=split(@") | 1,4s/$/\=remove(l,0)/
will transform
work it
make it
do it
makes us
harder
better
faster...
Randomize a List
...uffle();
The code above uses the much criticised System.Random method to select swap candidates. It's fast but not as random as it should be. If you need a better quality of randomness in your shuffles use the random number generator in System.Security.Cryptography like so:
using System.Security....
MySQL: What's the difference between float and double?
...INSERT INTO `test` values (1.2,1.2,1.2,1.2);
The table showing like this:
SELECT * FROM `test`;
+------+------+------+------+
| fla | flb | dba | dbb |
+------+------+------+------+
| 1.2 | 1.2 | 1.20 | 1.20 |
+------+------+------+------+
See the difference?
We try to next example:
SELECT ...
what is reverse() in Django
... question = get_object_or_404(Question, pk=question_id)
try:
selected = question.choice_set.get(pk=request.POST['choice'])
except KeyError:
# handle exception
pass
else:
selected.votes += 1
selected.save()
return HttpResponseRedirect(reve...
Should I use “hasClass” before “addClass”? [duplicate]
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Hey Jon :) It is mouse selectable as well.. (click on line number and shift+click on another to select all lines..)
– Gabriele Petrioli
Nov 13 '12 at 10:30
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