Reshaping a data frame
39758
Collapse / concatenate / aggregate a column to a single comma separated string within each group
61315
Concatenating a column by a group in R
26303
Add a new column between other dataframe columns
39134
Subset data frame based on number of rows per group
56687
Normalizing the value of columns in Dataset
13177
Numbering rows within groups in a data frame
135139
Convert data frame to list
104654
Transpose N rows with different columns into single column
151975
Appropriate data transformation
135319
Convert the values in a column into row names in an existing data frame
33391
Select rows in a dataframe in r based on values in one row
58082
How to Flatten a Multidimensional Array?
151542
How does one reorder columns in a data frame?
140331
For loop in R assigning to a data frame
58090
Drop unused factor levels in a subsetted data frame
142751
How do you remove columns from a data.frame?
79594
Convert factor to integer in a data frame