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javac : command not found
...led the Java Runtime Environment (JRE) only, which does not contain javac. For javac, you have to install the OpenJDK Development Environment. You can install java-devel or java-1.6.0-openjdk-devel, which both include javac.
By the way: you can find out which package provides javac with a yum searc...
Regex, every non-alphanumeric character except white space or colon
...
[^a-zA-Z\d\s:]
\d - numeric class
\s - whitespace
a-zA-Z - matches all the letters
^ - negates them all - so you get - non numeric chars, non spaces and non colons
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How does python numpy.where() work?
...n't seem to work well with more complex logical expressions though - for example I can't do np.where(a > 30 and a < 50) or np.where(30 < a < 50) because it ends up trying to evaluate the logical AND of two arrays of booleans, which is pretty meaningless. Is there a way to write such a co...
Check if a string is a date value
...h this as it will still return return for invalid dates in February, for example: 2013-02-31
– leojh
Feb 13 '13 at 22:47
62
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Best way to merge two maps and sum the values of same key?
...er value from that set. So integers under addition are a semigroup, for example - the + operator combines two ints to make another int.
You can also define a semigroup over the set of "all maps with a given key type and value type", so long as you can come up with some operation that combines two ...
Google Maps API 3 - Custom marker color for default (dot) marker
...i with the urls:
http://chart.apis.google.com/chart?chst=d_map_pin_letter&chld=%E2%80%A2|FE7569
Which looks like this: the image is 21x34 pixels and the pin tip is at position (10, 34)
And you'll also want a separate shadow image (so that it doesn't overlap nearby icons):
http://chart.apis...
Map vs Object in JavaScript
...often a pain with non-scalar types where you have to deal with things like PHP merges Array/Map with Object using A/M for properties and JS merges Map/Object with Array extending M/O. Merging complex types is the devil's bane of high level scripting languages.
So far these are largely issues around ...
How to get screen dimensions as pixels in Android
...t information for:
"The absolute width of the display in pixels."
Example:
Log.d("ApplicationTagName", "Display width in px is " + metrics.widthPixels);
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Check if at least two out of three booleans are true
...tLeastTwo(boolean a, boolean b, boolean c) {
return a ? (b || c) : (b && c);
}
or this (whichever you find easier to grasp):
boolean atLeastTwo(boolean a, boolean b, boolean c) {
return a && (b || c) || (b && c);
}
It tests a and b exactly once, and c at most onc...
What is the difference between . (dot) and $ (dollar sign)?
...ppears on the right to the input of whatever appears on the left. This usually also results in fewer parentheses, but works differently.
Going back to the same example:
putStrLn (show (1 + 1))
(1 + 1) doesn't have an input, and therefore cannot be used with the . operator.
show can take an Int...