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Introspecting Tables

Gabriel Becker and Adrian Waddell

2023-12-08

Source: vignettes/introspecting_tables.Rmd
introspecting_tables.Rmd

The packages used in this vignette are rtables and dplyr:

Introduction

First, let’s set up a simple table.

lyt <- basic_table(show_colcounts = TRUE) %>%
  split_cols_by("ARMCD") %>%
  split_cols_by("STRATA2") %>%
  split_rows_by("STRATA1") %>%
  add_overall_col("All") %>%
  summarize_row_groups() %>%
  analyze("AGE", afun = max, format = "xx.x")

tbl <- build_table(lyt, ex_adsl)
tbl
#                  ARM A                     ARM B                     ARM C                       
#             S1           S2           S1           S2           S1           S2           All    
#           (N=73)       (N=61)       (N=67)       (N=67)       (N=56)       (N=76)       (N=400)  
# —————————————————————————————————————————————————————————————————————————————————————————————————
# A       18 (24.7%)   20 (32.8%)   22 (32.8%)   22 (32.8%)   14 (25.0%)   26 (34.2%)   122 (30.5%)
#   max      40.0         46.0         62.0         50.0         47.0         45.0         62.0    
# B       28 (38.4%)   19 (31.1%)   19 (28.4%)   26 (38.8%)   18 (32.1%)   25 (32.9%)   135 (33.8%)
#   max      48.0         47.0         58.0         58.0         46.0         64.0         64.0    
# C       27 (37.0%)   22 (36.1%)   26 (38.8%)   19 (28.4%)   24 (42.9%)   25 (32.9%)   143 (35.8%)
#   max      48.0         50.0         48.0         51.0         69.0         50.0         69.0

Getting Started

We can get basic table dimensions, the number of rows, and the number of columns with the following code:

dim(tbl)
# [1] 6 7
nrow(tbl)
# [1] 6
ncol(tbl)
# [1] 7

Detailed Table Structure

The table_structure() function prints a summary of a table’s row structure at one of two levels of detail. By default, it summarizes the structure at the subtable level.

# [TableTree] STRATA1
#  [TableTree] A [cont: 1 x 7]
#   [ElementaryTable] AGE (1 x 7)
#  [TableTree] B [cont: 1 x 7]
#   [ElementaryTable] AGE (1 x 7)
#  [TableTree] C [cont: 1 x 7]
#   [ElementaryTable] AGE (1 x 7)

When the detail argument is set to "row", however, it provides a more detailed row-level summary which acts as a useful alternative to how we might normally use the str() function to interrogate compound nested lists.

table_structure(tbl, detail = "row")
# TableTree: [STRATA1] (STRATA1)
#   labelrow: [STRATA1] (STRATA1) - <not visible>
#   children: 
#     TableTree: [A] (A)
#       labelrow: [A] (A) - <not visible>
#       content:
#         ElementaryTable: [A@content] ()
#           labelrow: [] () - <not visible>
#           children: 
#             ContentRow: [A] (A)
#       children: 
#         ElementaryTable: [AGE] (AGE)
#           labelrow: [AGE] (AGE) - <not visible>
#           children: 
#             DataRow: [max] (max)
#     TableTree: [B] (B)
#       labelrow: [B] (B) - <not visible>
#       content:
#         ElementaryTable: [B@content] ()
#           labelrow: [] () - <not visible>
#           children: 
#             ContentRow: [B] (B)
#       children: 
#         ElementaryTable: [AGE] (AGE)
#           labelrow: [AGE] (AGE) - <not visible>
#           children: 
#             DataRow: [max] (max)
#     TableTree: [C] (C)
#       labelrow: [C] (C) - <not visible>
#       content:
#         ElementaryTable: [C@content] ()
#           labelrow: [] () - <not visible>
#           children: 
#             ContentRow: [C] (C)
#       children: 
#         ElementaryTable: [AGE] (AGE)
#           labelrow: [AGE] (AGE) - <not visible>
#           children: 
#             DataRow: [max] (max)

The make_row_df() and make_col_df() functions each create a data.frame with a variety of information about the table’s structure. Most useful for introspection purposes are the label, name, abs_rownumber, path and node_class columns (the remainder of the information in the returned data.frame is used for pagination)

make_row_df(tbl)[, c("label", "name", "abs_rownumber", "path", "node_class")]
#   label name abs_rownumber         path node_class
# 1     A    A             1 STRATA1,.... ContentRow
# 2   max  max             2 STRATA1,....    DataRow
# 3     B    B             3 STRATA1,.... ContentRow
# 4   max  max             4 STRATA1,....    DataRow
# 5     C    C             5 STRATA1,.... ContentRow
# 6   max  max             6 STRATA1,....    DataRow

There is also a wrapper function, row_paths() available for make_row_df to display only the row path structure:

# [[1]]
# [1] "STRATA1"  "A"        "@content" "A"       
# 
# [[2]]
# [1] "STRATA1" "A"       "AGE"     "max"    
# 
# [[3]]
# [1] "STRATA1"  "B"        "@content" "B"       
# 
# [[4]]
# [1] "STRATA1" "B"       "AGE"     "max"    
# 
# [[5]]
# [1] "STRATA1"  "C"        "@content" "C"       
# 
# [[6]]
# [1] "STRATA1" "C"       "AGE"     "max"

By default make_row_df() summarizes only visible rows, but setting visible_only to FALSE gives us a structural summary of the table with the full hierarchy of subtables, including those that are not represented directly by any visible rows:

make_row_df(tbl, visible_only = FALSE)[, c("label", "name", "abs_rownumber", "path", "node_class")]
#    label      name abs_rownumber         path      node_class
# 1          STRATA1            NA      STRATA1       TableTree
# 2                A            NA   STRATA1, A       TableTree
# 3        A@content            NA STRATA1,.... ElementaryTable
# 4      A         A             1 STRATA1,....      ContentRow
# 5              AGE            NA STRATA1,.... ElementaryTable
# 6    max       max             2 STRATA1,....         DataRow
# 7                B            NA   STRATA1, B       TableTree
# 8        B@content            NA STRATA1,.... ElementaryTable
# 9      B         B             3 STRATA1,....      ContentRow
# 10             AGE            NA STRATA1,.... ElementaryTable
# 11   max       max             4 STRATA1,....         DataRow
# 12               C            NA   STRATA1, C       TableTree
# 13       C@content            NA STRATA1,.... ElementaryTable
# 14     C         C             5 STRATA1,....      ContentRow
# 15             AGE            NA STRATA1,.... ElementaryTable
# 16   max       max             6 STRATA1,....         DataRow

make_col_df() similarly accepts visible_only, though here the meaning is slightly different, indicating whether only leaf columns should be summarized (defaults to TRUE) or whether higher level groups of columns - analogous to subtables in row space - should be summarized as well.

make_col_df(tbl)[, c("label", "name", "abs_pos", "path", "leaf_indices")]
#   label name abs_pos         path leaf_indices
# 1    S1   S1       1 ARMCD, A....            1
# 2    S2   S2       2 ARMCD, A....            2
# 3    S1   S1       3 ARMCD, A....            3
# 4    S2   S2       4 ARMCD, A....            4
# 5    S1   S1       5 ARMCD, A....            5
# 6    S2   S2       6 ARMCD, A....            6
# 7   All  All       7     All, All            7
make_col_df(tbl, visible_only = FALSE)[, c("label", "name", "abs_pos", "path", "leaf_indices")]
#    label  name abs_pos         path leaf_indices
# 1  ARM A ARM A      NA ARMCD, ARM A         1, 2
# 2     S1    S1       1 ARMCD, A....            1
# 3     S2    S2       2 ARMCD, A....            2
# 4  ARM B ARM B      NA ARMCD, ARM B         3, 4
# 5     S1    S1       3 ARMCD, A....            3
# 6     S2    S2       4 ARMCD, A....            4
# 7  ARM C ARM C      NA ARMCD, ARM C         5, 6
# 8     S1    S1       5 ARMCD, A....            5
# 9     S2    S2       6 ARMCD, A....            6
# 10   All   All       7     All, All            7

Similarly, there is wrapper function col_paths() available, which displays only the column structure:

# [[1]]
# [1] "ARMCD"   "ARM A"   "STRATA2" "S1"     
# 
# [[2]]
# [1] "ARMCD"   "ARM A"   "STRATA2" "S2"     
# 
# [[3]]
# [1] "ARMCD"   "ARM B"   "STRATA2" "S1"     
# 
# [[4]]
# [1] "ARMCD"   "ARM B"   "STRATA2" "S2"     
# 
# [[5]]
# [1] "ARMCD"   "ARM C"   "STRATA2" "S1"     
# 
# [[6]]
# [1] "ARMCD"   "ARM C"   "STRATA2" "S2"     
# 
# [[7]]
# [1] "All" "All"

The row_paths_summary() and col_paths_summary() functions wrap the respective make_*_df functions, printing the name, node_class, and path information (in the row case), or the label and path information (in the column case), indented to illustrate table structure:

# rowname    node_class    path                   
# ————————————————————————————————————————————————
# A          ContentRow    STRATA1, A, @content, A
#   max      DataRow       STRATA1, A, AGE, max   
# B          ContentRow    STRATA1, B, @content, B
#   max      DataRow       STRATA1, B, AGE, max   
# C          ContentRow    STRATA1, C, @content, C
#   max      DataRow       STRATA1, C, AGE, max
# label    path                     
# ——————————————————————————————————
# ARM A    ARMCD, ARM A             
#   S1     ARMCD, ARM A, STRATA2, S1
#   S2     ARMCD, ARM A, STRATA2, S2
# ARM B    ARMCD, ARM B             
#   S1     ARMCD, ARM B, STRATA2, S1
#   S2     ARMCD, ARM B, STRATA2, S2
# ARM C    ARMCD, ARM C             
#   S1     ARMCD, ARM C, STRATA2, S1
#   S2     ARMCD, ARM C, STRATA2, S2
# All      All, All

Applications

Knowing the structure of an rtable object is helpful for retrieving specific values from the table. For examples, see the Path Based Cell Value Accessing section of the Subsetting and Manipulating Table Contents vignette.

Understanding table structure is also important for post-processing processes such as sorting and pruning. More details on this are covered in the Pruning and Sorting Tables vignette vignette.

Summary

In this vignette you have learned a number of utility functions that are available for examining the underlying structure of rtable objects.