Not sure how to fix this error with my code

[Gintonic]

I am not sure why this error comes up or how to fix the problem.

    #turn the file into a data frame
    df <- data.frame(data = filename)
    df
    #check that all the rows are still in the data frame 
    nrow(df)
    # import ggplot2 into r
    library(ggplot2)
    #check all the headings for the data frame
    names(df)
    str(df)
    # create a df of regions
    regdata <- df[df$data.Area.type == "Region",]
    nrow(regdata)
    str(regdata)
    natdata <- df[df$data.Area.type == "Nation",]
    nrow(natdata)
    str(natdata)
    utladata <- df[df$data.Area.type == "Upper tier local authority",] 
    nrow(utladata)
    ltladata <- df[df$data.Area.type == "Lower tier local authority",]
    nrow(ltladata)
    str(df$data.Specimen.date)
    #chart regional cases rate
Please could you advice me.
p <- ggplot(data = 'regdata', aes(x = 'data.Specimen.date', y = 'data.Cumulative.lab.confirmed.cases.rate'))
p + geom_line()

[FJCC]

I do not see any error text in your post but I will take a guess. Do not use quotes around variable or column names when using ggplot. Try

p <- ggplot(data = regdata, aes(x = data.Specimen.date, y = data.Cumulative.lab.confirmed.cases.rate))
p + geom_line()

[HanOostdijk]

The change that @FJCC suggested is needed in any case, but I think you could also having trouble with reading the data. That is not done with

#turn the file into a data frame
    df <- data.frame(data = filename) # NOT CORRECT !

I give an example of (first writing some test data to a file and then) reading from a file in a data.frame :

# write some test data
filename = 'gintonic.txt'
mydata = data.frame(
  data.Specimen.date = 1:4,
  data.Cumulative.lab.confirmed.cases.rate = c(0.4, 0.3, 0.35, 0.45),
  data.Area.type = c("Region","Region","Nation","Nation")
)
write.csv(mydata,filename)

Your code could then look like

filename = 'gintonic.txt'
df = read.csv(filename)

# create a df of regions
regdata <- df[df$data.Area.type == "Region",]
nrow(regdata)

# import ggplot2 into r
library(ggplot2)

# and use the adapted code by FJCC:
p <- ggplot(data = regdata, 
            aes(x = data.Specimen.date, 
                y = data.Cumulative.lab.confirmed.cases.rate))
p + geom_line()