Alexander questions

• Selecting and renaming columns at the same time
• Remove groups that contain certain strings
• kmeans clustering in grouped data
• How to output the columns with the maximum value
• Dual y axis (second axis) use in ggplot2
• multiple separate arguments in 'tidyr's separate function
• wrapping long geom_text labels
• Error when using "diff" function inside of dplyr mutate
• how to change col names with the first row of a data in dplyr chain
• How to randomly subset of data with dplyr?

Alexander answers