R - Add/Remove Columns in Data Frame
• Data frames in R support multiple methods for adding columns: direct assignment ($), bracket notation ([]), and functions like cbind() and mutate() from dplyr
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R - Add/Remove Rows in Data Frame
The most straightforward approach uses rbind() to bind rows together. Create a new row as a data frame or list with matching column names:
Python - Add/Remove Elements from Set
The add() method inserts a single element into a set. Since sets only contain unique values, adding a duplicate element has no effect.