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python pandas dataframe to dictionary
I've a two columns dataframe, and intend to convert it to python dictionary - the first column will be the key and the second will be the value. Thank you in advance.
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MYSQL OR vs IN performance
... not believe people who give their "opinion", science is all about testing and evidence.
I ran a loop of 1000x the equivalent queries (for consistency, I used sql_no_cache):
IN: 2.34969592094s
OR: 5.83781504631s
Update:
(I don't have the source code for the original test, as it was 6 years ago, ...
IN clause and placeholders
I'm attempting to do the following SQL query within Android:
9 Answers
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Rails :include vs. :joins
... that requires it. In some cases, you know the join will be more efficient and will not incur the risk of duplication.
– Jonathan Swartz
Nov 21 '13 at 0:28
1
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How do I get the last inserted ID of a MySQL table in PHP?
...se, don't use mysql_* functions in new code. They are no longer maintained and are officially deprecated. See the red box? Learn about prepared statements instead, and use PDO or MySQLi - this article will help you decide which. If you choose PDO, here is a good tutorial.
But if you have to, use m...
Oracle SQL: Update a table with data from another table
...ere is no matching row in t2. Without it, every row in t1 will be updated and the values will be set to NULL if there is no matching row in t2. That is generally not what you want to happen so the WHERE EXISTS is generally needed.
– Justin Cave
Aug 5 '13 at 1...
How to remove item from list in C#?
...s {
public int ID; public string FirstName; public string LastName;
}
and assigned some values to results as follows:
var results=new List<myClass> {
new myClass() { ID=1, FirstName="Bill", LastName="Smith" },
new myClass() { ID=2, FirstName="John", LastName="Wilson" },
new ...
Explicitly set Id with Doctrine when using “AUTO” strategy
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Thank you and I'm happy to help a bit as I can :)
– nicolasbui
Dec 5 '12 at 18:20
2
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SQL select only rows with max value on a column [duplicate]
...ou join your table to the sub-query with equality on both group-identifier and max-value-in-group:
SELECT a.id, a.rev, a.contents
FROM YourTable a
INNER JOIN (
SELECT id, MAX(rev) rev
FROM YourTable
GROUP BY id
) b ON a.id = b.id AND a.rev = b.rev
Left Joining with self, tweaking join...
Bundle ID Suffix? What is it?
...ple asks for the Bundle ID Suffix. What is this? Not sure what to put here and what the significance of it is.
2 Answers
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