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Determine the data types of a data frame's columns
...ation as a vector (i.e. you don't need it to do something else programmatically later), just use str(foo).
In both cases foo would be replaced with the name of your data frame.
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ERROR 1044 (42000): Access denied for user ''@'localhost' to database 'db'
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how can I go to bash?I had problem installing mysql see here superuser.com/questions/377679/… I just know abt it in command line
– Nickool
Jan 12 '12 at 17:01
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What's the valid way to include an image with no src?
I have an image that I will dynamically populate with a src later with javascript but for ease I want the image tag to exist at pageload but just not display anything. I know <img src='' /> is invalid so what's the best way to do this?
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Difference between val() and text()
...ut element -- regardless of type. .text() gets the innerText (not HTML) of all the matched elements:
.text()
The result is a string that contains
the combined text contents of all
matched elements. This method works on
both HTML and XML documents. Cannot be
used on input elements. For i...
CSS3 Spin Animation
... because you explained it best and you are the only answer that included all the prefixed versions.
– iambriansreed
Feb 13 '13 at 18:07
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Cleaning `Inf` values from an R dataframe
...ption 1
Use the fact that a data.frame is a list of columns, then use do.call to recreate a data.frame.
do.call(data.frame,lapply(DT, function(x) replace(x, is.infinite(x),NA)))
Option 2 -- data.table
You could use data.table and set. This avoids some internal copying.
DT <- data.table(dat)...
How do I find Waldo with Mathematica?
... over the weekend: What is a good way to solve those Where's Waldo? [ 'Wally' outside of North America] puzzles, using Mathematica (image-processing and other functionality)?
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Run PHP Task Asynchronously
...egistration' button, I don't want to make them wait until the email is actually sent, I just want to start the process, and return a message to the user right away.
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Django - limiting query results
...s are lazy. That means a query will hit the database only when you specifically ask for the result.
So until you print or actually use the result of a query you can filter further with no database access.
As you can see below your code only executes one sql query to fetch only the last 10 items.
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Grabbing the href attribute of an A element
...ml($node), PHP_EOL;
}
The above would find and output the "outerHTML" of all A elements in the $html string.
To get all the text values of the node, you do
echo $node->nodeValue;
To check if the href attribute exists you can do
echo $node->hasAttribute( 'href' );
To get the href att...