Suggestion: check results of operation, not what was typed literally

[alexey-guryanov]

It looks like swirl checks what was typed literally. Say, if it's requested to load data with read.csv, and read.csv(path, stringsAsFactors=FALSE) is expected, then read.csv(path, stringsAsFactors=F) is rejected as incorrect.

It may be a better approach to treat student's input as black box, and check the result instead: specific variable, some side effect, etc.