How to deal with Cronbach's alpha "data must either be a data frame or a matrix" error?

Question

I have imported my data. The columns in question only contain numbers and NA.

I try to compute the cronbach's-alpha between my 4 variables as follows (there are more variables in the dataframe):

library(psych)

alpha (df$column1, df$column2, df$column3, df$columns4)

I get the following error:

Data must either be a data frame or a matrix

What could be the problem / the solution? This is probably very basic. But so am I. Thanks in advance!

Greetings from Berlin Paul

Answer 1

Here is one work around

df <- data.frame(df$column1, df$column2, df$column3, df$columns4)
alpha(df)

See ?alpha for detail.
The input alpha expects is a data.frame or matrix of data, or a covariance or correlation matrix. You can create a dataframe out of the desired columns and pass that to alpha with additional arguments if you want.