String Conversion- For loop on categorical variables - r

Question

Hi all I am a novice to R and appreciate your hints on this case.
I've been struggling to convert the variables (objects) in my dataframe to strings and plot them using a for loop, as detailed below.
COUNTRY: China Belgium ...
COMPANY: XXX Inc. YYY Inc. ...
Here, COUNTRY and COMPANY are categorical variables.
I've used toString() as well as as.character() to convert variable name to a string so I can specify the plot name but I cant seem to get it to work. I need 4 variable as listed in code below in for loop for 2 purposes:
as String for naming plot
use in barplot()
but neither string conversion nor the for loop is working properly as I meant to.
Could somebody assist me with the proper command for this purpose?
Your help is greatly appreciated...
Kind regards,
CODE
Frequency_COUNTRY <- table(COUNTRY)#Get Frequency for COUNTRY
Relative_Frequency_COUNTRY <- table(COUNTRY) / length(COUNTRY)#Get Relative
#Frequency (Percentage %) for Variable COUNTRY
Frequency_COMPANY <- table(COMPANY) #Get Frequency and Relative Frequency for COMPANY
Relative_Frequency_COMPANY <- table(COMPANY) / length(COMPANY)
Categorical_Variable_List = c(Frequency_COUNTRY,
Relative_Frequency_COUNTRY ,
Frequency_COMPANY,
Relative_Frequency_COMPANY)`# Get list of 4 variables above
for (Categorical_Variable in Categorical_Variable_List){#Plot 4 variables using a for loop
A = toString(Categorical_Variable) #Trying to convert non-string variable name to string
plotName <- paste("BarChart_", A, sep = "_")# Specify plot name, e.g. BarChart_Frequency_COUNTRY
png(file = plotName)#Create png file
barplot(Categorical_Variable) #use barplot() to make graph
dev.off()`# Switch off dev
}

Answer 1

Your code is treating Categorical_Variable_List as if it were a named list of categorical variables. It is neither.
The following code corrects those errors and plots a graph of 4 barplots. In your code, remove the two calls to par, one before and the other after the for loop.
I will make up a dataset, to test the code.
set.seed(1234)
n <- 20
COUNTRY <- sample(LETTERS[1:5], n, TRUE)
COMPANY <- sample(letters[1:4], n, TRUE)
Frequency_COUNTRY <- table(COUNTRY) # Get Frequency for COUNTRY
Relative_Frequency_COUNTRY <- table(COUNTRY) / length(COUNTRY)#Get Relative
# Frequency (Percentage %) for Variable COUNTRY
Frequency_COMPANY <- table(COMPANY) # Get Frequency and Relative Frequency for COMPANY
Relative_Frequency_COMPANY <- table(COMPANY) / length(COMPANY)
Variable_List <- list(Frequency_COUNTRY = Frequency_COUNTRY,
Relative_Frequency_COUNTRY = Relative_Frequency_COUNTRY,
Frequency_COMPANY = Frequency_COMPANY,
Relative_Frequency_COMPANY = Relative_Frequency_COMPANY) # Get list of 4 variables above
Variable_Name <- names(Variable_List)
old_par <- par(mfrow = c(2, 2))
for (i in seq_along(Variable_List)){ # Plot 4 variables using a for loop
plotName <- paste("BarChart", Variable_Name[[i]], sep = "_") # Specify plot name
print(plotName) # for debugging only
#png(file = plotName) # Create png file
barplot(Variable_List[[i]]) # use barplot() to make graph
#dev.off() # Switch off dev
}
par(old_par)