How to add columns to a data frame in R

How to add columns to a data frame in R?, To add one or more columns to a data frame in R, use the mutate() function from the dplyr package.

With the following data frame, the following examples demonstrate how to use this syntax in practice.

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How to add columns to a data frame in R

Let’s create a data frame

df <- data.frame(player = c('P1', 'P2', 'P3', 'P4', 'P5', 'P6', 'P7'),
                 points = c(122, 144, 154, 155, 120, 218, 229),
                 assists = c(43, 55, 77, 18, 114, NA,29))

Now we can view the data frame

df

    player points assists
1     P1    122      43
2     P2    144      55
3     P3    154      77
4     P4    155      18
5     P5    120     114
6     P6    218      NA
7     P7    229      29

Approach 1: Add Column at End of Data Frame

The following code demonstrates how to add a column to the data frame’s end.

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at the end of the data frame, add a ‘blocks’ column

df <- df %>%
  mutate(score=c(1, 3, 3, 2, 4, 3, 6))

Let’s view the data frame

df

   player points assists score
1     P1    122      43     1
2     P2    144      55     3
3     P3    154      77     3
4     P4    155      18     2
5     P5    120     114     4
6     P6    218      NA     3
7     P7    229      29     6

It’s worth noting that you may create an empty column by just giving NA to each of the new column’s values.

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at the conclusion of the data frame, add an empty column

df <- df %>%
        mutate(blocks=NA)

df

    player points assists score
1     P1    122      43    NA
2     P2    144      55    NA
3     P3    154      77    NA
4     P4    155      18    NA
5     P5    120     114    NA
6     P6    218      NA    NA
7     P7    229      29    NA

Approach 2: Add Column Before Specific Column

The following code demonstrates how to insert a column in front of a certain column in a data frame:

insert the ‘score’ column after the ‘points’ column.

df <- df %>%
        mutate(score=c(1, 3, 3, 2, 4, 3, 6),
              .before=points)

df

   player points assists score
1     P1    122      43     1
2     P2    144      55     3
3     P3    154      77     3
4     P4    155      18     2
5     P5    120     114     4
6     P6    218      NA     3
7     P7    229      29     6

Approach 3: Add Column After Specific Column

The following code demonstrates how to add a column to the data frame after a certain column.

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Following the ‘points’ column, add a ‘score’ column

df <- df %>%
        mutate(blocks=c(1, 3, 3, 2, 4, 3, 6),
              .after=points)
df

player points blocks assists score
1     P1    122      1      43     1
2     P2    144      3      55     3
3     P3    154      3      77     3
4     P4    155      2      18     2
5     P5    120      4     114     4
6     P6    218      3      NA     3
7     P7    229      6      29     6

Approach 4: Add Column Based on Other Columns

The following code demonstrates how to add a column in a data frame based on another column.

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add a ‘status’ column whose values are based on the ‘points’ column’s value

df <- df %>%
        mutate(status= if_else(.$points > 20, 'Good', 'Bad'))
df

   player points blocks assists score status
1     P1    122      1      43     1   Good
2     P2    144      3      55     3   Good
3     P3    154      3      77     3   Good
4     P4    155      2      18     2   Good
5     P5    120      4     114     4   Good
6     P6    218      3      NA     3   Good
7     P7    229      6      29     6   Good