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How does one reorder columns in a data frame?
...
You can also use the subset function:
data <- subset(data, select=c(3,2,1))
You should better use the [] operator as in the other answers, but it may be useful to know that you can do a subset and a column reorder operation in a single command.
Update:
You can also use the select...
How to automatically generate getters and setters in Android Studio
...ar -> Code -> Generate...
and then using shift or control button, select all the variables you need to add getters and setters
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How to remove all MySQL tables from the command-line without DROP database permissions? [duplicate]
...tatements to execute it:
SET FOREIGN_KEY_CHECKS = 0;
SET @tables = NULL;
SELECT GROUP_CONCAT('`', table_schema, '`.`', table_name, '`') INTO @tables
FROM information_schema.tables
WHERE table_schema = 'database_name'; -- specify DB name here.
SET @tables = CONCAT('DROP TABLE ', @tables);
PRE...
COUNT(*) vs. COUNT(1) vs. COUNT(pk): which is better? [duplicate]
...for all your queries that need to count everything, even for joins, use *
SELECT boss.boss_id, COUNT(subordinate.*)
FROM boss
LEFT JOIN subordinate on subordinate.boss_id = boss.boss_id
GROUP BY boss.id
But don't use COUNT(*) for LEFT joins, as that will return 1 even if the subordinate table doe...
What is the difference between single and double quotes in SQL?
...ould be more readable as product_id, so you use either of the following:
SELECT PRODUCT.id AS product_id
SELECT PRODUCT.id 'product_id'
Either works in Oracle, SQL Server, MySQL… but I know some have said that the TOAD IDE seems to give some grief when using the single quotes approach.
You do...
Replacement for “rename” in dplyr
...
The next version of dplyr will support an improved version of select that also incorporates renaming:
> mtcars2 <- select( mtcars, disp2 = disp )
> head( mtcars2 )
disp2
Mazda RX4 160
Mazda RX4 Wag 160
Datsun 710 108
Hornet 4 Drive 258
H...
How to save MySQL query output to excel or .txt file? [duplicate]
...SV file:
MySQL provides an easy mechanism for writing the results of a select
statement into a text file on the server. Using extended options of
the INTO OUTFILE nomenclature, it is possible to create a comma
separated value (CSV) which can be imported into a spreadsheet
application suc...
iOS 7 - Failing to instantiate default view controller
...ard, click anywhere in the white area and press command-a, then command-c (select all and copy)
Open your new storyboard and press command-v to paste the same exact setup
Go to your project settings, change your "Main Interface" to the new Main_iPhoneV2 (If it's your iPad and you're writing a univer...
When is an interface with a default method initialized?
...p->local_interfaces()->at(i);
InstanceKlass* ik = InstanceKlass::cast(iface);
if (ik->has_default_methods() && ik->should_be_initialized()) {
ik->initialize(THREAD);
....
}
}
}
So this initialization has been implemented explicitly as a new Step 7.5. T...
Password reset for Azure database
...ic Windows Azure SQL Database server, you can do this from the new portal. Select the Database choice on the left, then select Servers:
Then, after selecting the server of choice, you'll see the option on the right for resetting admin password:
...