invalid escape sequence when open csv file in julia

The problem is that Julia interprets \O, \. and \w in this example as an escape sequence, but since neither of those is a valid escape sequence, that is why you get a syntax error with that error message, ie:

julia> path = "D:\Online_Courses\...\wikipediaEVDraw.csv"
ERROR: syntax: invalid escape sequence
Stacktrace:
 [1] top-level scope at REPL[32]:0

Escape \ with \\ because you want to interpret \ as a literal backslash, not as the beginning of an escape sequence:

julia> path = "D:\\Online_Courses\\...\\wikipediaEVDraw.csv"
"D:\\Online_Courses\\...\\wikipediaEVDraw.csv"

And then this will work:

julia> wikiEVDraw = CSV.read("D:\\Online_Courses\\...\\wikipediaEVDraw.csv")

Or use @raw_str string macro to do it automatically:

julia> path = raw"D:\Online_Courses\...\wikipediaEVDraw.csv"
"D:\\Online_Courses\\...\\wikipediaEVDraw.csv"

So you can do:

julia> wikiEVDraw = CSV.read(raw"D:\Online_Courses\...\wikipediaEVDraw.csv")

Or you can also use forward slashes / for paths as in Linux or MacOS instead of the backslash \ for windows specific paths inside strings:

julia> wikiEVDraw = CSV.read("D:/Online_Courses/.../wikipediaEVDraw.csv")