在R中的图上添加数据点

Question

Hi I have a simple plot of years and the number of births across those years. I want to create a graph/line that has the years on the x axis and the number on the y. My code so far is below. when I run it I get the error Error in jitter(x) : 'x' must be numeric. The plot is based on a dataframe df. Any help would be greatly appreciated.

#plot(df$Number),(df$sex),xlab="x",ylab="y",type="l",main= "My graph")
plot(df$Year,df$Number)
x = df$Year
y = df$Number
#plot(x,y)

par(mar=c(3,3,2,1),mgp=c(2,0.7,0),las=1)
plot(x,y,type="n",xaxt="n",yaxt="n",las=1,xlab="Years",ylab="")
title("Number Of Births")
axis(1,at=pretty(x),labels=TRUE)
axis(2,at=pretty(y,n=10),las=1)
#grid()

points(jitter(x),y,col="blue",pch=20)

#points(jitter(df$Number))

Answer 1

See what class(x) or class(df$Year) says.

Depending on the data, its easy to see Year being treated as a factor.