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Reverse the values of an Object in R Programming – rev() Function
• Last Updated : 17 Jun, 2020

`rev()` function in R Language is used to return the reverse version of data objects. The data objects can be defined as Vectors, Data Frames by Columns & by Rows, etc.

Syntax: rev(x)

Parameter:
x: Data object

Returns: Reverse of the data object passed

Example 1:

 `# R program to reverse a vector ` ` `  `# Create a vector ` `vec <``-` `1``:``5`                            `vec   ` ` `  `# Apply rev() function to vector     ` `vec_rev <``-` `rev(vec)                       ` `vec_rev                                   `

Output:

```[1] 1 2 3 4 5
[1] 5 4 3 2 1
```

Example 2: Reverse Columns of a Data Frame

 `# R program to reverse  ` `# columns of a Data Frame ` ` `  `# Creating a data.frame ` `data <``-` `data.frame(x1 ``=` `1``:``5``,             ` `                   ``x2 ``=` `6``:``10``, ` `                   ``x3 ``=` `11``:``15``) ` `data  ` `  `  `# Print reversed example data frame ` `data_rev <``-` `rev(data)                     ` `data_rev `

Output:

```   x1 x2 x3
1  1  6 11
2  2  7 12
3  3  8 13
4  4  9 14
5  5 10 15

x3 x2 x1
1 11  6  1
2 12  7  2
3 13  8  3
4 14  9  4
5 15 10  5
```

Example 3: Reverse Rows of a Data Frame

 `# R program to reverse ` `# rows of a data frame ` ` `  `# Creating a data frame ` `data <``-` `data.frame(x1 ``=` `1``:``5``,             ` `                   ``x2 ``=` `6``:``10``, ` `                   ``x3 ``=` `11``:``15``) ` `data  ` `  `  `# Calling rev() & apply() functions combined ` `data_rev_row_a <``-` `apply``(data, ``2``, rev)     ` `data_rev_row_a  ` ` `  `# Alternative without rev()   ` `data_rev_row_b <``-` `data[nrow(data):``1``, ]    ` `data_rev_row_b `

Output:

```  x1 x2 x3
1  1  6 11
2  2  7 12
3  3  8 13
4  4  9 14
5  5 10 15
x1 x2 x3
[1,]  5 10 15
[2,]  4  9 14
[3,]  3  8 13
[4,]  2  7 12
[5,]  1  6 11
x1 x2 x3
5  5 10 15
4  4  9 14
3  3  8 13
2  2  7 12
1  1  6 11
```

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