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Extracting specific columns from a data frame
...r package, if your data.frame is called df1:
library(dplyr)
df1 %>%
select(A, B, E)
This can also be written without the %>% pipe as:
select(df1, A, B, E)
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...
What is the most compatible way to install python modules on a Mac?
...o for MacPorts be aware that multiple versions of the same package are not selected anymore like the old Debian style with an extra python_select package (it is still there for compatibility). Now you have the select command to choose which Python version will be used (you can even select the Apple ...
Get filename and path from URI from mediastore
I have an onActivityResult returning from an mediastore image selection which I can get a URI for an image using the following:
...
How to export table as CSV with headings on Postgresql?
...
@arilwan psql -c "\COPY (SELECT * FROM mytable) TO STDOUT" > mytable.csv
– Juha Palomäki
Jun 6 '19 at 16:00
...
Selecting the first “n” items with jQuery
With Jquery, I need to select just the first "n" items from the page, for example the first 20 links instead of selecting all of them with the usual
...
Why can't radio buttons be “readonly”?
...ton by disabling only the un-checked radio buttons. It keeps the user from selecting a different value, and the checked value will always post on submit.
Using jQuery to make readonly:
$(':radio:not(:checked)').attr('disabled', true);
This approach also worked for making a select list readonly, ...
SQL Server Insert if not exists
..., Assunto, Data)
VALUES (@_DE, @_ASSUNTO, @_DATA)
WHERE NOT EXISTS ( SELECT * FROM EmailsRecebidos
WHERE De = @_DE
AND Assunto = @_ASSUNTO
AND Data = @_DATA);
END
replace with
BEGIN
IF NOT EXISTS (SELECT * FROM EmailsRecebidos
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Is it possible to use raw SQL within a Spring Repository
... @user454322, parameters start with 1, so it's: @Query(value = "SELECT * FROM USERS WHERE EMAIL_ADDRESS = ?1", nativeQuery = true)
– Jacob van Lingen
Jan 6 '17 at 9:20
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jQuery $(“#radioButton”).change(…) not firing during de-selection
...Andomar's solution worked but this makes more sense to me. Using the class selector prevents having to change the function if the form changes or has a dynamic number of fields. Yay for necro votes! (though now 2 years later jQuery recommends using prop() instead of attr(). api.jquery.com/prop)
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Which timestamp type should I choose in a PostgreSQL database?
...al time zone
test=> SET timezone = 'America/Los_Angeles';
SET
test=> SELECT NOW();
now
-------------------------------
2011-05-27 15:47:58.138995-07
(1 row)
test=> SELECT NOW() AT TIME ZONE 'UTC';
timezone
----------------------------
2011-...