@Dawn Chin - Welcome to Microsoft Q&A and thanks for reaching out.
If you ever see the Error in ggplot(...): could not find function "ggplot", it suggests that this ggplot() function is not available because the package that holds the function (ggplot2) did not load with library(ggplot2).
Therefore, you cannot utilize the ggplot() function without that ggplot2 package being loaded first.
Hope this helps. and please feel free to reach out if you have any further questions.
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