colnames()

The colnames() function returns or sets the names of the columns in a data frame.

The column names can be retrieved and set using the following syntax:

# Retrival
colnames(df_object)

# Setting
colnames(df_object) <- value

• The df_object parameter is the object passed into the colnames() function.
• The value is a vector containing column names; its length must be equal to the amount of columns in the original df_object.

The following example uses a CSV file named "transactions.csv" file with the following information in it:

The column names can be retrieved by reading the file and using the colnames() function:

df <- read.csv("transactions.csv")

colnames(df)

This returns the following:

[1] "Date"         "Time"         "Total"        "Card"

The column names can be changed as follows:

# Reading CSV file
df <- read.csv("transactions.csv")

# Change column names
colnames(df) <- c("day", "hour", "subamount", "member")

# Retrieve column names
colnames(df)

The above yields the data with the new column names:

[1] "day"       "hour"      "subamount"   "member"