Hello, I have a big table with 3 columns and 103918 rows. This is the example,
time species dbh
5 1 4.9377297
575 1 11.64127213
575 1 109.8182438
575 1 8.029809521
5 1 24.32501874
575 1 4.895992119
575 1 11.40567637
575 1 2.795090562
575 1 21.79281837
575 1 52.57476174
575 1 27.7290919
575 1 3.23262083
575 2 19.30612651
575 1 2.956672964
575 1 111.690689
575 1 11.82499086
575 1 63.86200585
575 1 111.8312759
575 1 49.23078501
25 1 2.810866156
575 1 10.93097209
575 1 23.7930745
575 1 21.68010008
575 1 13.32423271
575 1 23.10306499
575 1 59.646657
1000 2 20.47707761
575 1 3.255755538
575 1 29.3392412
575 1 2.578551542
575 1 52.71564453
575 1 119.8069955
575 1 83.45738555
575 1 7.763555744
725 1 2.578551542
I would like to calculate the dbh mean but only for species 1, time 575. I have
tried this
> names (exp1)
[1] "time" "species" "dbh"
> time = c(1)
> species=c(2)
> dbh=c(3)
> dbhmean <- mean (exp1 [time==575 & species ==1])
> dbhmean
named list()
I am not sure why it appears the message "named list()"...
Can anybody give me some hints on how to do this correctly?
Thanks.
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