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A Regex that will never be matched by anything
...atch a character a after the end of the string. Good luck.
WARNING:
This expression is expensive -- it will scan the entire line, find the end-of-line anchor, and only then not find the a and return a negative match. (See comment below for more detail.)
* Originally I did not give much thought o...
Passing functions with arguments to another function in Python?
...
I find that the limited syntax is nearly opaque; they're hard to explain to n00bz. Yes, they do work here, and the confusing features of the syntax are absent. This is -- perhaps -- the only example I've seen of a lambda that's not obscure.
...
Where do I find old versions of Android NDK? [closed]
...he link to the NDK that you want and download it from dl.google.com:
Linux example:
http://dl.google.com/android/ndk/android-ndk-r9b-linux-x86.tar.bz2
http://dl.google.com/android/ndk/android-ndk-r9b-linux-x86_64.tar.bz2
OS X example:
http://dl.google.com/android/ndk/android-ndk-r9b-darwin-x86.ta...
How to validate an email address in PHP
...emailaddress
}
Additionally you can check whether the domain defines an MX record:
if (!checkdnsrr($domain, 'MX')) {
// domain is not valid
}
But this still doesn't guarantee that the mail exists. The only way to find that out is by sending a confirmation mail.
Now that you have your eas...
Python: Find in list
... the elements inside myList. Maybe you try to find a string that does not exactly match one of the items or maybe you are using a float value which suffers from inaccuracy.
As for your second question: There's actually several possible ways if "finding" things in lists.
Checking if something is in...
Can't get rid of header X-Powered-By:Express
I am running a server on nodejs with express. I can't seem to get rid of the header:
13 Answers
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Determine if two rectangles overlap each other?
...ts from the user to construct rectangles (between 2 and 5): height, width, x-pos, y-pos. All of these rectangles will exist parallel to the x and the y axis, that is all of their edges will have slopes of 0 or infinity.
...
Principal component analysis in Python
....
I have not had the chance to test it myself, but I've bookmarked it exactly for the PCA functionality.
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Resetting generator object in Python
...rsion of your generator:
y = FunctionWithYield()
y, y_backup = tee(y)
for x in y:
print(x)
for x in y_backup:
print(x)
This could be beneficial from memory usage point of view if the original iteration might not process all the items.
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Extracting the last n characters from a string in R
...'s straight-forward to make a function to do this using substr and nchar:
x <- "some text in a string"
substrRight <- function(x, n){
substr(x, nchar(x)-n+1, nchar(x))
}
substrRight(x, 6)
[1] "string"
substrRight(x, 8)
[1] "a string"
This is vectorised, as @mdsumner points out. Cons...