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How to check that an object is empty in PHP?
...ray) $obj) does not work in PHP 5.4+ has nothing to do with typecasting on one line. You get the error because empty() takes a reference to the variables passed to it, and it cannot get a reference when typecasting unless you first store that typecasted variable in another variable. It does this bec...
Why does one use dependency injection?
...posable, IEnumerable or IPrintable. A class is an actual implementation of one or more of these interfaces: List or Map may both be implementations of IEnumerable.
To get the point: Often your classes depend on each other. E.g. you could have a Database class which accesses your database (hah, surp...
The Use of Multiple JFrames: Good or Bad Practice? [closed]
... The user sees multiple icons in their task bar when expecting to see only one. Plus the side effects of the coding problems..
A nightmare to code and maintain:
A modal dialog offers the easy opportunity to focus attention on the content of that dialog - choose/fix/cancel this, then proceed. Mul...
How does one remove an image in Docker?
... Remove untagged images: docker rmi $(docker images | grep "^<none>" | awk "{print $3}")
– Barrett Clark
Oct 5 '15 at 16:11
1
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Call apply-like function on each row of dataframe with multiple arguments from each row
...from the dplyr package:
> library(dplyr)
> myf <- function(tens, ones) { 10 * tens + ones }
> x <- data.frame(hundreds = 7:9, tens = 1:3, ones = 4:6)
> mutate(x, value = myf(tens, ones))
hundreds tens ones value
1 7 1 4 14
2 8 2 5 25
3 9 ...
Why does one hot encoding improve machine learning performance?
I have noticed that when One Hot encoding is used on a particular data set (a matrix) and used as training data for learning algorithms, it gives significantly better results with respect to prediction accuracy, compared to using the original matrix itself as training data. How does this performance...
Semaphore vs. Monitors - what's the difference?
...ions or methods of a monitor object will enforce mutual exclusion, so only one thread may be performing any action on the object at a given time. If one thread is currently executing a member function of the object then any other thread that tries to call a member function of that object will have t...
What do all of Scala's symbolic operators mean?
... them. For example, <= on Int means "less than or equal to". The first one, ->, I'll give as example below. :: is probably the method defined on List (though it could be the object of the same name), and :+= is probably the method defined on various Buffer classes.
So, let's see them.
Keywo...
Rails: create on has_one association
...work. However there is a big difference between has_many relations and has_one relations:
With a has_many relation, shops returns an ActiveRecord collection object, which has methods that you can use to add and remove shops to/from a user. One of those methods is create, which creates a new shop an...
JMS Topic vs Queues
...
That means a topic is appropriate. A queue means a message goes to one and only one possible subscriber. A topic goes to each and every subscriber.
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