[BioC] Special Characters? (flowViz | R question)

[M. Jankowski]

Hi All,

Thank you all very much for your previous help answering my newbie questions!

I am working my way through the filter.pdf document that pertains to
the flowViz package. When I copy this text from the *.pdf:

xyplot(`SSC-H` ~ `FSC-H` | Visit, data = GvHD, filter = n2gate,
displayFilter = TRUE, subset = Patient == "6")

I see the plot indicated in the pdf.  Type in this:

xyplot('SSC-H' ~ 'FSC-H' | Visit, data = GvHD, filter=n2gate,
displayFilter=TRUE, subset = Patient == "6")

and I get a bunch of errors. The difference seems to be '  vs `. What
is reason for using ` vs ' or even "? Is there a resource that I can
use to look up special characters like this? I've searched through the
help files/etc. and no luck so far.

Thanks!
Matt


There were 42 warnings (use warnings() to see them)
> warnings()
Warning messages:
1: NAs introduced by coercion in: as.double.default(x)
2: NAs introduced by coercion in: as.double.default(y)
3: no non-missing arguments to min; returning Inf in: min(x[, id])
4: no non-missing arguments to max; returning -Inf in: max(x[, id])
5: no non-missing arguments to min; returning Inf in: min(x[, id])
6: no non-missing arguments to max; returning -Inf in: max(x[, id])
7: NAs introduced by coercion in: as.double.default(x)
8: NAs introduced by coercion in: as.double.default(y)
9: no non-missing arguments to min; returning Inf in: min(x[, id])
10: no non-missing arguments to max; returning -Inf in: max(x[, id])
11: no non-missing arguments to min; returning Inf in: min(x[, id])
12: no non-missing arguments to max; returning -Inf in: max(x[, id])
13: NAs introduced by coercion in: as.double.default(x)
14: NAs introduced by coercion in: as.double.default(y)
15: no non-missing arguments to min; returning Inf in: min(x[, id])
16: no non-missing arguments to max; returning -Inf in: max(x[, id])
17: no non-missing arguments to min; returning Inf in: min(x[, id])
18: no non-missing arguments to max; returning -Inf in: max(x[, id])
19: NAs introduced by coercion in: as.double.default(x)
20: NAs introduced by coercion in: as.double.default(y)
21: no non-missing arguments to min; returning Inf in: min(x[, id])
22: no non-missing arguments to max; returning -Inf in: max(x[, id])
23: no non-missing arguments to min; returning Inf in: min(x[, id])
24: no non-missing arguments to max; returning -Inf in: max(x[, id])
25: NAs introduced by coercion in: as.double.default(x)
26: NAs introduced by coercion in: as.double.default(y)
27: no non-missing arguments to min; returning Inf in: min(x[, id])
28: no non-missing arguments to max; returning -Inf in: max(x[, id])
29: no non-missing arguments to min; returning Inf in: min(x[, id])
30: no non-missing arguments to max; returning -Inf in: max(x[, id])
31: NAs introduced by coercion in: as.double.default(x)
32: NAs introduced by coercion in: as.double.default(y)
33: no non-missing arguments to min; returning Inf in: min(x[, id])
34: no non-missing arguments to max; returning -Inf in: max(x[, id])
35: no non-missing arguments to min; returning Inf in: min(x[, id])
36: no non-missing arguments to max; returning -Inf in: max(x[, id])
37: NAs introduced by coercion in: as.double.default(x)
38: NAs introduced by coercion in: as.double.default(y)
39: no non-missing arguments to min; returning Inf in: min(x[, id])
40: no non-missing arguments to max; returning -Inf in: max(x[, id])
41: no non-missing arguments to min; returning Inf in: min(x[, id])
42: no non-missing arguments to max; returning -Inf in: max(x[, id])
>