R rowMeans() function is used to calculate the mean of each row of a data frame or matrix.

**Syntax**

`rowMeans(x, na.rm = FALSE)`

**Parameters**

**x:**It is an array of two or more dimensions containing numeric, complex, integer, or logical values or a numeric data frame.**na.rm:**It is a logical argument. If**TRUE**, NA values are ignored.

**Example 1: Calculating the mean of every row of a data frame**

```
# Create data frame
df <- data.frame(
player1 = c(11, 55, 99, 444, 888),
player2 = c(22, 66, 111, 555, 999),
player3 = c(33, 77, 222, 666, 11),
player4 = c(44, 88, 333, 777, 22)
)
# Calculating the mean of every row using rowMeans() function
rowMeans(df)
```

**Output**

```
[1] 27.50 71.50 191.25 610.50 480.00
```

We calculated the mean of the values across each row using the **rowMeans()** function, effectively providing the average value for each player across the columns.

**Example 2: Calculating the ****mean of every row and excluding NA values**

As you can see from the figure, we get the output NA for every row because every row contains NA values.

```
# Create a data frame.
df <- data.frame(
col1 = c(NA, 2, 3),
col2 = c(4, NA, 6),
col3 = c(7, 8, NA)
)
# Calculate the mean of data frame
rowMeans(df)
```

**Output**

```
[1] NA NA NA
```

You can exclude **NA** values while calculating the mean of every row by passing the **na.rm = TRUE** parameter to the rowMeans() function.

```
# Create a data frame.
df <- data.frame(
col1 = c(NA, 2, 3),
col2 = c(4, NA, 6),
col3 = c(7, 8, NA)
)
# Calculate the mean of data frame
rowMeans(df, na.rm = TRUE)
```

**Output**

```
[1] 5.5 5.0 4.5
```

**Example 3: Calculating the mean of specific rows**

```
# Create a data frame.
df <- data.frame(
col1 = c(1, 2, 3),
col2 = c(4, 5, 6),
col3 = c(7, 8, 9)
)
rowMeans(df[c(1, 3), ])
```

**Output**

```
1 3
4 6
```

From the output and figure, you can see that for **row 1, the mean is 4, and for row 2, the mean is 6**.

**Example 4: Calculating the mean of every row of the matrix**

```
# Create a matrix.
mat <- matrix(1:9, 3, 3)
print(mat)
# Calculate the mean of each row.
cat("The mean of every row of matrix: ", rowMeans(mat), "\n")
```

**Output**

```
The mean of every row of matrix: 4 5 6
```

**See also**

Krunal Lathiya is a seasoned Computer Science expert with over eight years in the tech industry. He boasts deep knowledge in Data Science and Machine Learning. Versed in Python, JavaScript, PHP, R, and Golang. Skilled in frameworks like Angular and React and platforms such as Node.js. His expertise spans both front-end and back-end development. His proficiency in the Python language stands as a testament to his versatility and commitment to the craft.