I am having a terrible time figuring out this script. I am working with camera trap data, and have variables for camera name, species, and time of day species was captured on camera (day or night). I want to know for each camera, how many times each species occurred during the day. Ultimately I am looking for a variable, perc.day, of the percent of occurrences during the day for each species for each camera. perc.day would be # of "day" detections / all total detections for each species on each camera. I have been using dplyr and data.table.
Here is a sample of what the data looks like:
camera <- c('A', 'A', 'A', 'A', 'B', 'B', 'B', 'C', 'C', 'C', 'C', 'C')
species <- c('deer', 'deer', 'deer', 'coyote', 'deer', 'deer', 'deer', 'deer', 'coyote', 'coyote', 'coyote', 'bobcat')
time_cat <- c('day', 'day', 'night', 'day', 'night', 'day', 'day', 'day', 'night', 'day', 'night', 'night')
data <- data.frame(camera, species, time_cat)
And what I need it to look like:
camera <- c('A', 'A', 'B', 'C', 'C', 'C')
species <- c('deer', 'coyote', 'deer', 'deer', 'coyote', 'bobcat')
total.detections <- c('3', '1', '3', '1', '3', '1')
perc.day <- c('0.667', '0', '0.667', '100', '0.333', '0')
data.final <- data.frame(camera, species, total.detections, perc.day)
This code works up to the detections variable, but at a loss for how to get the perc.day variable
data.final <-
data %>%
group_by(camera, species) %>%
summarize(total.detections = n())
Thank you for any help or advice.
A final mutate and ungroup on top of your original solution does the trick:
data %>%
group_by(camera, species) %>%
summarize(total.detections = n(),
day_count = sum(time_cat == "day")) %>%
ungroup() %>%
mutate(per.day = day_count / total.detections)
# # A tibble: 6 × 5
# camera species total.detections day_count per.day
# <chr> <chr> <int> <int> <dbl>
# 1 A coyote 1 1 1
# 2 A deer 3 2 0.667
# 3 B deer 3 2 0.667
# 4 C bobcat 1 0 0
# 5 C coyote 3 1 0.333
# 6 C deer 1 1 1