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PHP: How to check if image file exists?
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130
You need the filename in quotation marks at least (as string):
if (file_exists('http://www.myd...
How to succinctly write a formula with many variables from a data frame?
... the . identifier.
y <- c(1,4,6)
d <- data.frame(y = y, x1 = c(4,-1,3), x2 = c(3,9,8), x3 = c(4,-4,-2))
mod <- lm(y ~ ., data = d)
You can also do things like this, to use all variables but one (in this case x3 is excluded):
mod <- lm(y ~ . - x3, data = d)
Technically, . means all ...
How to concatenate string variables in Bash
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30 Answers
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Can two applications listen to the same port?
...ple applications can subscribe to the same port.
Edit: Since Linux Kernel 3.9 and later, support for multiple applications listening to the same port was added using the SO_REUSEPORT option. More information is available at this lwn.net article.
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Efficient way to remove keys with empty strings from a dict
...n 2.X
dict((k, v) for k, v in metadata.iteritems() if v)
Python 2.7 - 3.X
{k: v for k, v in metadata.items() if v is not None}
Note that all of your keys have values. It's just that some of those values are the empty string. There's no such thing as a key in a dict without a value; if it d...
Is it possible to get all arguments of a function as single object inside that function?
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348
Use arguments. You can access it like an array. Use arguments.length for the number of argumen...
Python JSON serialize a Decimal object
I have a Decimal('3.9') as part of an object, and wish to encode this to a JSON string which should look like {'x': 3.9} . I don't care about precision on the client side, so a float is fine.
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How to listen for a WebView finishing loading a URL?
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730
Extend WebViewClient and call onPageFinished() as follows:
mWebView.setWebViewClient(new WebVi...
Run php script as daemon process
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Henrik P. HesselHenrik P. Hessel
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