epi_clean_class_to_factor: Convert column class to factor if unique values below cutoff

In AntonioJBT/episcout: Quickly Clean, Explore and Visualise Large Epidemiological Datasets

Description

Convert column class to factor if column has less than x unique results. Useful for handling data frames with many columns with some automation for specifying column classes. Assumes that columns with fewer unique values than the cutoff parameter should be read as factors. All column classes other than dates are converted. Assumes that eg integer columns with few values are in fact coded factors.

Usage

epi_clean_class_to_factor(df = NULL, cutoff_unique = 10)

Arguments

df	A data frame object with columns to convert to factor
cutoff_unique	A cutoff for the number of unique values present in the column. Column class will be converted if there are less unique values than the cutoff. Default is 10.

Value

The data frame passed with classes converted.

Note

Avoids converting dates to factors if class is already Date. Note that lubridate converted dates may return eg "POSIXct" "POSIXt" which return a logical vector > 1 (for each element) and give a warning message (that can be ignored): "... the condition has length > 1 and only the first element will be used"

Author(s)

Antonio Berlanga-Taylor <https://github.com/AntonioJBT/episcout>

See Also

epi_clean_count_classes, epi_clean_cond_date, epi_clean_cond_chr_fct, epi_clean_cond_numeric

Examples

## Not run: 
n <- 20
df_factor <- data.frame(
var_id = rep(1:(n / 2), each = 2),
var_to_rep = rep(c('Pre', 'Post'), n / 2),
x = rnorm(n),
y = rbinom(n, 1, 0.50),
z = rpois(n, 2)
)
df_factor$date_col <- seq(as.Date("2018/1/1"),
by = "year", length.out = 5)#nrow(df_factor))
# Check the current classes:
lapply(df_factor, class)
# Check how many unique values within each column:
lapply(df_factor, function(x) length(unique(x)))
# Check conditions:
i <- 'date_col'
cutoff_unique <- 10
# if num. of unique values is less than cut-off:
length(unique(df_factor[[i]])) < cutoff_unique # should be TRUE
# and the class is not already a date:
class(df_factor[[i]]) != "Date" # should be FALSE
df_factor <- epi_clean_class_to_factor(df_factor, cutoff_unique = 10)
lapply(df_factor, class)
df_factor

## End(Not run)

AntonioJBT/episcout documentation built on Nov. 7, 2019, 5:34 p.m.