Hello,
I have a dataframe as follows:
```
x = c("0 pmol", "10 pmol", "100 pmol", "1000 pmol")
y = c(0.9306, 1.8906, 2.2396, 2.7917)
df = data.frame(x, y)> str(df) 'data.frame': 4 obs. of 2 variables: $ x: chr "0 pmol" "10 pmol" "100 pmol" "1000 pmol" $ y: num 0.931 1.891 2.24 2.792 ``` I would like to visualize the data with the classic dots (pch=16) but: ``` > plot(df$y ~ df$x) Error in plot.window(...) : need finite 'xlim' values In addition: Warning messages: 1: In xy.coords(x, y, xlabel, ylabel, log) : NAs introduced by coercion 2: In min(x) : no non-missing arguments to min; returning Inf 3: In max(x) : no non-missing arguments to max; returning -Inf ``` which is right because x is not numeric, so I took the factor: ``` plot(df$y ~ factor(df$x)) # gives bars instead of dots plot(df$y ~ factor(df$x), pch = 16) # this also ``` I tried to convert directly the dataframe: ``` df$x = lapply(df$x, factor) > str(df) 'data.frame': 4 obs. of 2 variables: $ x:List of 4 ..$ : Factor w/ 1 level "0 pmol": 1 ..$ : Factor w/ 1 level "10 pmol": 1 ..$ : Factor w/ 1 level "100 pmol": 1 ..$ : Factor w/ 1 level "1000 pmol": 1 $ y: num 0.931 1.891 2.24 2.792 > plot(r$y ~ r$x, pch = 16) Error in plot.window(...) : need finite 'xlim' values In addition: Warning messages: 1: In xy.coords(x, y, xlabel, ylabel, log) : NAs introduced by coercion 2: In min(x) : no non-missing arguments to min; returning Inf 3: In max(x) : no non-missing arguments to max; returning -Inf ``` If I try to pass the number of levels: ``` plot(df$y ~ factor(df$x, 1:4), pch = 16) # this draw a boxplot with all data on level 1 > df$x = lapply(df$x, factor(1:4)) Error in match.fun(FUN) : 'factor(1:4)' is not a function, character or symbol ``` Since the transformation has given only one level (1), my questions are: How do I tell R to use a dot instead of a line? What is the correct way of setting factors? -- Best regards, Luigi ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
