错误：在 R 中找不到 object。 标题未命名来自.csv 文件

Question

I am new to R and I keep getting inconsistent results with trying to display a column of data from a csv. I am able to import the csv into R without issue, but I can't call out the individual columns.

Here's my code:

setwd('mypath')
cdata <- read.csv(file="cendata.csv",header=TRUE, sep=",")
cdata

This prints out the following:

   year       pop
1  2010 2,775,332
2  2011 2,814,384
3  2012 2,853,375
4  2013 2,897,640
5  2014 2,936,879
6  2015 2,981,835
7  2016 3,041,868
8  2017 3,101,042
9  2018 3,153,550
10 2019 3,205,958

When I try to plot the following, the columns cannot be found.

plot(pop,year)

Error: object 'pop' not found

I even checked if the column names existed, and only data shows up.

ls()
[1] "data" 

I can manually enter the data and label them "pop" and "year" but that kind of defeats the point of importing the csv.

Is there a way to label each header as an object?

Answer 1

year and pop are not independent objects. You need to refer them as part of the dataframe you have imported. Also you might need to remove "," from the numbers to turn them to numeric before plotting. Try:

cdata$pop <- as.numeric(gsub(',', '', cdata$pop))
plot(cdata$year, cdata$pop)