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Numbering rows within groups in a data frame
Working with a data frame similar to this:
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How to assign colors to categorical variables in ggplot2 that have stable mapping?
I've been getting up to speed with R in the last month.
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Is an array an object in java
In java we can declare an array like
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What does .class mean in Java?
What does .class mean in Java? For example, if I created a class called Print . What does Print.class return?
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Unit Testing AngularJS directive with templateUrl
I have an AngularJS directive that has a templateUrl defined. I am trying to unit test it with Jasmine.
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What is the rationale for all comparisons returning false for IEEE754 NaN values?
Why do comparisons of NaN values behave differently from all other values?
That is, all comparisons with the operators ==, =, where one or both values is NaN returns false, contrary to the behaviour of all other values.
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How do I run all Python unit tests in a directory?
I have a directory that contains my Python unit tests. Each unit test module is of the form test_*.py . I am attempting to make a file called all_test.py that will, you guessed it, run all files in the aforementioned test form and return the result. I have tried two methods so far; both have fail...
How to trace the path in a Breadth-First Search?
How do you trace the path of a Breadth-First Search, such that in the following example:
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How to split a string in shell and get the last field
Suppose I have the string 1:2:3:4:5 and I want to get its last field ( 5 in this case). How do I do that using Bash? I tried cut , but I don't know how to specify the last field with -f .
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belongs_to through associations
Given the following associations, I need to reference the Question that a Choice is attached through from the Choice model. I have been attempting to use belongs_to :question, through: :answer to perform this action.
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