Error in if testduplicatedcases argument is of length zero

This error occurs when you are trying to check for duplicated cases in a dataset using the duplicated() function, but the argument you are passing to the function has a length of zero.

To resolve this error, you need to make sure that you are passing a valid argument to the duplicated() function. Here are a few possible solutions:

1. Check if the dataset you are using is empty or has no observations. If this is the case, you need to load or generate a dataset with some data before checking for duplicated cases.

2. Make sure that the variable you are using to check for duplicated cases exists in the dataset and is not empty. If the variable you are using does not exist or is empty, you will get this error.

3. If you are subsetting the dataset before checking for duplicated cases, ensure that the subset you are using is not empty. If the subset is empty, you will get this error.

Make sure to double-check your code and the data you are using to identify the cause of this error and apply the appropriate solution