hello everyone. please bear with me if this is very easy...
I have a data set with many trials, and frames within each trial. I would
like to pull out one random frame from each trial.
here is an example. i have 4 unique trials (file), and various frames within
each (time_pred). I would like to randomly sample 4 rows, but 1 from each
trial (file).
this sample data is called "h"
file time_pred distance_1 distance_2
distance_3
1 12.03.08_ins_odo_01 210 19.003 18.023 14.666
2 12.03.08_ins_odo_01 240 23.905 20.087 17.266
3 12.03.08_ins_odo_01 270 15.694 9.285 4.135
4 12.03.08_ins_odo_02 0 22.142 16.061 14.776
5 12.03.08_ins_odo_02 30 2.968 12.533 19.696
6 12.03.08_ins_odo_02 60 6.175 17.701 20.198
7 12.03.08_ins_odo_02 90 13.668 12.950 13.506
8 12.03.08_ins_odo_02 120 7.098 17.817 22.878
9 12.03.08_ins_odo_02 270 17.252 18.235 18.661
10 12.03.08_ins_odo_02 300 7.967 15.944 8.130
11 12.03.08_ins_odo_03 90 18.724 17.931 21.148
12 12.03.08_ins_odo_03 120 21.220 26.370 23.962
13 12.03.08_ins_odo_03 150 21.225 24.376 20.194
14 12.03.08_ins_odo_03 180 22.298 24.119 24.606
15 12.03.08_ins_odo_03 210 8.413 14.464 15.219
16 12.03.08_ins_odo_03 240 18.117 19.111 19.870
17 12.03.08_ins_odo_07 60 24.063 25.779 24.800
18 12.03.08_ins_odo_07 90 19.790 23.276 18.678
19 12.03.08_ins_odo_07 120 15.617 23.707 19.545
20 12.03.08_ins_odo_07 150 24.818 22.373 24.515
21 12.03.08_ins_odo_07 180 16.301 19.976 25.309
22 12.03.08_ins_odo_07 210 23.843 24.772 26.025
23 12.03.08_ins_odo_07 240 9.029 15.125 20.139
24 12.03.08_ins_odo_07 270 6.533 22.833 23.618
here is my code so far...
> random <-for(i in unique(file)){h[sample(1:24,1),]}
> random
but this only gives me one sample... and if I try to exclude naming it as
random, then nothing comes up. i'm confused and very new to R. please help!
many many thanks!
kristiina
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