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How can I check if multiplying two numbers in Java will cause an overflow?
I want to handle the special case where multiplying two numbers together causes an overflow. The code looks something like this:
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How to compare two floating point numbers in Bash?
I am trying hard to compare two floating point numbers within a bash script. I have to variables, e.g.
17 Answers
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This project references NuGet package(s) that are missing on this computer
I have an ASP.NET MVC5 application that worked yesterday and now I am getting this error when I try to build:
18 Answers
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What to use as an initial version? [closed]
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My versioning is driven by the setup. I want it to replace older versions, so I keep increasing it in jumps that make sense to me.
Sometimes, however, versioning is driven by the customer, especially if you're releasing code to the p...
How to shift a column in Pandas DataFrame
I would like to shift a column in a Pandas DataFrame , but I haven't been able to find a method to do it from the documentation without rewriting the whole DF. Does anyone know how to do it?
DataFrame:
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Display a float with two decimal places in Python
I have a function taking float arguments (generally integers or decimals with one significant digit), and I need to output the values in a string with two decimal places (5 -> 5.00, 5.5 -> 5.50, etc). How can I do this in Python?
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How do I temporarily disable triggers in PostgreSQL?
I'm bulk loading data and can re-calculate all trigger modifications much more cheaply after the fact than on a row-by-row basis.
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How do you convert an entire directory with ffmpeg?
How do you convert an entire directory/folder with ffmpeg via command line or with a batch script?
24 Answers
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To find whether a column exists in data frame or not
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Assuming that the name of your data frame is dat and that your column name to check is "d", you can use the %in% operator:
if("d" %in% colnames(dat))
{
cat("Yep, it's in there!\n");
}
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Should I use a data.frame or a matrix?
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Part of the answer is contained already in your question: You use data frames if columns (variables) can be expected to be of different types (numeric/character/logical etc.). Matrices are for data of the same type.
Consequently, the choice matrix/da...