4 Basic operations
The first step is to initialise the flowchart with
as_fc. The last step, if we want to visualise the created
flowchart, is to draw the flowchart with fc_draw. In
between we can combine the functions fc_split.,
fc_filter, fc_merge, fc_stack
with the operator pipe (|> or %>$) to
create complex flowchart structures.
4.1 Initialize
To initialize a flowchart from a dataset we have to use the
as_fc() function:
## List of 2
## $ data: tibble [925 × 21] (S3: tbl_df/tbl/data.frame)
## $ fc : tibble [1 × 22] (S3: tbl_df/tbl/data.frame)
## - attr(*, "class")= chr "fc"The safo_fc object created is a fc object,
which consists of a list containing the tibble of the
data.frame associated with the flowchart and the tibble
that stores the flowchart parameters. In this example,
safo_fc$data corresponds to the safo dataset
while safo_fc$fc contains the parameters of the initial
flowchart:
## # A tibble: 1 × 22
## id x y n N perc label text_pattern text type group just
## <dbl> <dbl> <dbl> <int> <int> <chr> <chr> <chr> <chr> <chr> <lgl> <chr>
## 1 1 0.5 0.5 925 925 100 Init… "{label}\n{… "Ini… init NA cent…
## # ℹ 10 more variables: text_color <chr>, text_fs <dbl>, text_fface <dbl>,
## # text_ffamily <lgl>, text_padding <dbl>, bg_fill <chr>, border_color <chr>,
## # width <lgl>, height <lgl>, end <lgl>Alternatively, if a data.frame is not available, we can
initialize a flowchart using the N = argument manually
specifying the number of rows:
4.2 Draw
The function fc_draw() allows to draw the flowchart
associated to any fc object. Following the last example, we
can draw the initial flowchart that has been previously created:
4.3 Filter
We can filter the flowchart using fc_filter() specifying
the logic in which the filter is to be applied. For example, we can show
the number of patients that were randomized in the study:
safo |>
as_fc(label = "Patients assessed for eligibility") |>
fc_filter(!is.na(group), label = "Randomized", show_exc = TRUE) |>
fc_draw()
Percentages are calculated from the box in the previous level. See
‘Modify function arguments’ for more information on the
label= and show_exc= arguments.
Alternatively, if the column to filter is not available, we can use
the N = argument to manually specify the number of rows of
the resulting filter:
safo |>
as_fc(label = "Patients assessed for eligibility") |>
fc_filter(N = 215, label = "Randomized", show_exc = TRUE) |>
fc_draw()
4.4 Split
We can split the flowchart into groups using fc_split()
specifying the grouping variable. The function will split the flowchart
into as many categories as the specified variable has. For example, we
can split the previous flowchart showing the patients allocated in the
two study treatments:
safo |>
dplyr::filter(!is.na(group)) |>
as_fc(label = "Randomized patients") |>
fc_split(group) |>
fc_draw()
Percentages are calculated from the box in the previous level.
Alternatively, if the column to split is not available, we can use
the N = argument to manually specify the number of rows in
each group of the resulting split:
safo |>
dplyr::filter(!is.na(group)) |>
as_fc(label = "Randomized patients") |>
fc_split(N = c(105, 110), label = c("cloxacillin plus fosfomycin", "cloxacillin alone")) |>
fc_draw()
The idea is to combine the fc_filter() and
fc_split() functions in the way we want to create different
flowchart structures, however complex the may be.
4.5 Export
Once the flowchart has been drawn we can export it to the most
popular image formats, including both bitmap (png, jpeg, tiff, bmp) and
vector (svg, pdf) formats, using fc_export():
safo |>
as_fc(label = "Patients assessed for eligibility") |>
fc_filter(!is.na(group), label = "Randomized", show_exc = TRUE) |>
fc_draw() |>
fc_export("flowchart.png")We can change the size and resolution of the stored image.