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Select Pandas rows based on list index
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For large datasets, it is memory efficient to read only selected rows via the skiprows parameter.
Example
pred = lambda x: x not in [1, 3]
pd.read_csv("data.csv", skiprows=pred, index_col=0, names=...)
This will now return a DataFrame from a file that skips all rows except 1 and ...
Getting an empty JQuery object
In the following code I set up a change handler on a select box to show and hide some follow up questions based on the value of the selection.
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LINQ to SQL Left Outer Join
...table), where-as yours matches only 0-1. To do a left outer join, you need SelectMany and DefaultIfEmpty, for example:
var query = from c in db.Customers
join o in db.Orders
on c.CustomerID equals o.CustomerID into sr
from x in sr.DefaultIfEmpty()
s...
Select Row number in postgres
How to select row number in postgres.
1 Answer
1
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jQuery Set Cursor Position in Text Area
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I have two functions:
function setSelectionRange(input, selectionStart, selectionEnd) {
if (input.setSelectionRange) {
input.focus();
input.setSelectionRange(selectionStart, selectionEnd);
}
else if (input.createTextRange) {
var range = inpu...
Parameterize an SQL IN clause
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Here's a quick-and-dirty technique I have used:
SELECT * FROM Tags
WHERE '|ruby|rails|scruffy|rubyonrails|'
LIKE '%|' + Name + '|%'
So here's the C# code:
string[] tags = new string[] { "ruby", "rails", "scruffy", "rubyonrails" };
const string cmdText = "select * from t...
How can I insert values into a table, using a subquery with more than one result?
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You want:
insert into prices (group, id, price)
select
7, articleId, 1.50
from article where name like 'ABC%';
where you just hardcode the constant fields.
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How can I copy the output of a command directly into my clipboard?
...mewhere else other than a X application, try this one:
cat file | xclip -selection clipboard
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Which version of PostgreSQL am I running?
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Run this query from PostgreSQL:
SELECT version();
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SQL SERVER: Get total days between two dates
...:09.3312722';
DECLARE @enddate datetime2 = '2009-05-04 12:10:09.3312722';
SELECT DATEDIFF(day, @startdate, @enddate);
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