Remove an entire column from a data.frame in R
You can set it to NULL. As pointed out in the comments, here are some other possibilities: You can remove multiple columns via: Be careful with matrix-subsetting though, as you can end up with a vector:
Generating a Random Number between 1 and 10 Java [duplicate]
As the documentation says, this method call returns “a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive)”. This means that you will get numbers from 0 to 9 in your case. So you’ve done everything correctly by adding one to that number. Generally speaking, if you need to generate numbers from min to max (including both), … Read more
Adding values to a C# array
You can do this way – Alternatively, you can use Lists – the advantage with lists being, you don’t need to know the array size when instantiating the list.
“No viable overloaded ‘=’ ” why?
I’m making a project for one of my classes and I’m pretty sure I’m almost done with the project. Basically I have to input 2 people’s tickets and I have to find the maximum and minimum price. I need to overload the * and / operators to fix that issue for the project. Also, the friend declaration … Read more
The equivalent of a GOTO in python [duplicate]
Gotos are universally reviled in computer science and programming as they lead to very unstructured code. Python (like almost every programming language today) supports structured programming which controls flow using if/then/else, loop and subroutines. The key to thinking in a structured way is to understand how and why you are branching on code. For example, lets pretend … Read more
What does ** (double star/asterisk) and * (star/asterisk) do for parameters?
The *args and **kwargs is a common idiom to allow arbitrary number of arguments to functions as described in the section more on defining functions in the Python documentation. The *args will give you all function parameters as a tuple: The **kwargs will give you all keyword arguments except for those corresponding to a formal parameter as a dictionary. Both idioms can be mixed with normal arguments to … Read more
INSERT statement conflicted with the FOREIGN KEY constraint – SQL Server
In your table dbo.Sup_Item_Cat, it has a foreign key reference to another table. The way a FK works is it cannot have a value in that column that is not also in the primary key column of the referenced table. If you have SQL Server Management Studio, open it up and sp_help ‘dbo.Sup_Item_Cat‘. See which column that FK … Read more
Scroll to an element with jQuery
Assuming you have a button with the id button, try this example: I got the code from the article Smoothly scroll to an element without a jQuery plugin. And I have tested it on the example below.
RuntimeWarning: invalid value encountered in double_scalars – without numpy
The error is simply used to indicate a division where the denominator is of 0 value, e.g. your data somehow contains incorrect values, for example you try to take the square root of negative numbers, or 1/a where a (which is an array) contains zeroes. I am not able to reproduce the same error from the code … Read more
How to convert int to string on Arduino?
Use like this: You can find more examples here.