Hi Sumitrajit,
dplyr has a function for this - it's called filter.
For each group you can count the number of SNR > 3 (you can use sum on
true/false). You can filter on the results directly or add a column as
you plan. The latter might make your intention more clear.
HTH
Ulrik
On 2018-05-30 18:18, Sumitrajit Dhar wrote:
Hi Folks,
I have just started using dplyr and could use some help getting
unstuck. It could well be that dplyr is not the package to be using,
but let me just pose the question and seek your advice.
Here is my basic data frame.
head(h)
subject ageGrp ear hearingGrp sex freq L2 Ldp Phidp
NF SNR
1 HALAF032 A L A F 2 0 -23.54459 55.56005
-43.08282 19.538232
2 HALAF032 A L A F 2 2 -32.64881 86.22040
-23.31558 -9.333224
3 HALAF032 A L A F 2 4 -18.91058 42.12168
-35.60250 16.691919
4 HALAF032 A L A F 2 6 -23.85937 297.94499
-20.70452 -3.154846
5 HALAF032 A L A F 2 8 -14.45381 181.75329
-24.17094 9.717128
6 HALAF032 A L A F 2 10 -20.42384 67.12998
-35.77357 15.349728
'subject' and 'freq' together make a set of data and I am interested
in how the last four columns vary as a function of L2. So I grouped by
'subject' and 'freq' and can look at basic summaries.
h_byFunc <- h %>% group_by(subject, freq)
h_byFunc %>% summarize(l = mean(Ldp), s = sd(Ldp) )
# A tibble: 1,175 x 4
# Groups: subject [?]
subject freq l s
<fct> <int> <dbl> <dbl>
1 HALAF032 2 -13.8 8.39
2 HALAF032 4 -15.8 11.0
3 HALAF032 8 -23.4 6.51
4 HALAF033 2 -14.2 9.64
5 HALAF033 4 -12.3 8.92
6 HALAF033 8 -6.55 12.3
7 HALAF036 2 -14.9 12.6
8 HALAF036 4 -16.7 11.2
9 HALAF036 8 -21.7 6.56
10 HALAF039 2 0.242 12.4
# ... with 1,165 more rows
What I would like to do is filter some groups out based on various
criteria. For example, if SNR > 3 in three consecutive L2 within a
group, that group qualifies and I would add a column, say "clean" and
assign it a value "Y." Is there a way to do this in dplyr or should I
be looking at a different way.
Thanks in advance for your help.
Regards,
Sumit
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