The **rcorr()** function from **Hmisc** package is used to create correlation matrix in R.

The following method shows how you can do it with syntax.

**Method 1: Use rcorr() Function**

```
library(Hmisc)
rcorr(as.matrix(df))
```

The following example shows how to use **rcorr()** function in R to create correlation matrix.

## Using rcorr() Function

Let’s see how we can use **rcorr()** function in R:

```
# Import library
library(Hmisc)
# Create data frame
df <- data.frame(Pressure1=c(78.2, 88.2, 71.7, 80.21, 84.21, 82.56, 72.12, 73.85),
Temperature=c(35, 36, 37, 38, 32, 30, 31, 34),
Pressure2=c(12, 13, 11, 12, 14, 15, 13, 15))
# Create matrix of correlation coefficients and matrix of p-values
rcorr(as.matrix(df))
```

Output:

```
Pressure1 Temperature Pressure2
Pressure1 1.00 -0.03 0.27
Temperature -0.03 1.00 -0.71
Pressure2 0.27 -0.71 1.00
n= 8
P
Pressure1 Temperature Pressure2
Pressure1 0.9484 0.5242
Temperature 0.9484 0.0467
Pressure2 0.5242 0.0467
```

As in the output it shows correlation coefficient matrix and matrix of p-value.