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Computed / calculated / virtual / derived columns in PostgreSQL
...al, but makes makes life a bit easier).
Suppose my computation is md5(some_string_field), then I create the index as:
CREATE INDEX some_string_field_md5_index ON some_table(MD5(some_string_field));
Now, any queries that act on MD5(some_string_field) will use the index rather than computing it f...
Linq Query keeps throwing “Unable to create a constant value of type System.Object…”, Why?
...tBindingSource.Position =
accountBindingSource.IndexOf(_dataService.Db.Accounts.First(ac => ac.AccountName == name));
accountBindingSource_CurrentChanged(sender, e);
}
buggy code:
private void onTopAccBtnClick(object sender, EventArgs e)
{
accountBin...
What does the “@” symbol mean in reference to lists in Haskell?
...r any constructor; if you have data Tree a = Tree a [Tree a], then t@(Tree _ kids) gives you access to both the tree and its children.
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Line continuation for list comprehensions or generator expressions in python
...so you can pretty much do as you please. I'd personally prefer
[something_that_is_pretty_long
for something_that_is_pretty_long
in somethings_that_are_pretty_long]
The reason why \ isn't appreciated very much is that it appears at the end of a line, where it either doesn't stand out or needs...
How to perform mouseover function in Selenium WebDriver using Java?
...worked for me as well when adding .perform()
– TheRed__
Feb 27 '15 at 13:19
1
Cant belive this is...
Fit background image to div
...is the most appropriated one.
Source:
http://www.w3schools.com/cssref/css3_pr_background-size.asp
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Where can I learn jQuery? Is it worth it?
...ion
http://www.amazon.com/jQuery-Action-Bear-Bibeault/dp/1933988355/ref=sr_1_1?ie=UTF8&s=books&qid=1219716122&sr=1-1 (I bought it used at Amazon for about $22). It has been a big help into bootstrapping me into jQuery. The documentation at jquery.com are also very helpful.
A place wher...
iOS 5 Best Practice (Release/retain?)
...time compatibility glue code to your app. This works for everything except __weak variables, which require more support than the compatibility code can provide. ARC on iOS 4 is simpler than non-ARC code, but it's not as simple as ARC on iOS 5." By the way, the WWDC schedule app was written with AR...
What is the difference between tree depth and height?
... about to add quote with same content from here: en.wikipedia.org/wiki/Tree_%28data_structure%29
– Péter Török
Apr 8 '10 at 21:53
2
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How to keep index when using pandas merge
...
In [5]: a.reset_index().merge(b, how="left").set_index('index')
Out[5]:
col1 to_merge_on col2
index
a 1 1 1
b 2 3 2
c 3 4 NaN
Note that for some left merge operati...