Adapt get_custom_effort

[damianooldoni]

This PR will solve #333.

Thanks @MartijnUH for the very well description of the requested feature and the code.

I think I adapted get_custom_effort as you wished.

Test it hard please 🔨

Can you please test the PR and so review it? Thanks.
You can install this PR directly in R:

devtools::install_github("inbo/camtraptor", ref = "pull/335/head")

Notice that in the example on how to calculate the total effort over all deployments (added as example in function documentation), I needed to add dplyr::filter(effort > 0) to your provided code, otherwise I get all deployments in deploymentIDs, ndep and nloc:

get_custom_effort(mica, group_by = "year", unit = "day") %>%
  dplyr::filter(effort > 0) %>%
  dplyr::group_by(begin) %>% 
  dplyr::summarise(
    deploymentIDs = list(deploymentID),
    locationNames = list(locationName),
    ndep = length(unique(deploymentID)),
    nloc = length(unique(locationName)),
    effort = sum(effort),
    unit = unique(unit)
  )

[MartijnUH]

@damianooldoni see review below:

[MartijnUH]

Include a new assert_that to check for NAs in package$data$deployments$start and package$data$deployments$end to prevent the uniformative error message: Error in seq.int(0, to0 - from, by) : 'to' must be a finite number. See comment on R95.

[MartijnUH]

@damianooldoni the function seems to behave as intended. The only minor issue that I have found is that the function returns an uninformative error message (i.e. Error in seq.int(0, to0 - from, by) : 'to' must be a finite number) when either start or end columns of package$data$deployments contains NAs. This could be improved by returning a more informative error message.

I suggest that after these first assert_that checks, another check should evaluate if the start and end columns of the deployments do not contain NAs:

• include new assert_that to check for NAs in package$data$deployments$start and package$data$deployments$end

[damianooldoni]

Thanks @MartijnUH. I will check it. I also got an email so I could find your comment there 👍