Fix report() crash when character vector has only one unique value

[Copilot]

Description

Fixes a bug where report() would crash with an error when processing a character vector containing only one unique value.

The Problem

When calling report() on a character vector with a single unique value (e.g., c("big") or c("big", "big", "big")), the function would fail with:

Error in names(n_char) <- c("Entry", "n_Entry") : 
'names' attribute [2] must be the same length as the vector [1]

This also affected data frames containing such character columns, preventing analysis of datasets where categorical variables had only one level.

Root Cause

The issue was in report_table.character() where as.data.frame(sort(table(x), decreasing = TRUE)) creates a data frame with only 1 column (instead of the expected 2) when the table has a single unique value. Additionally, report_parameters.character() and report_statistics.character() would generate NA values when attempting to slice param_text[1:n_entries] with more entries requested than available.

Changes Made

1. Fixed table conversion in report_table.character(): Changed from as.data.frame(sort(table(x), decreasing = TRUE)) to a two-step process that ensures proper column structure:

   n_char <- as.data.frame(table(x))
   n_char <- n_char[order(n_char$Freq, decreasing = TRUE), ]

2. Fixed indexing in report_parameters.character() and report_statistics.character(): Added bounds checking to prevent NA values when n_entries exceeds the number of unique values:

   n_entries_actual <- min(n_entries, length(param_text))

Examples

The fix now works correctly for all cases:

library(report)

# Single unique value in a data frame (original issue)
df <- data.frame(id = 1:6, size = "big")
report(df)
#> The data contains 6 observations of the following 2 variables:
#>   - id: n = 6, Mean = 3.50, SD = 1.87, ...
#>   - size: 1 entry, such as big (n = 6) (0 missing)

# Single character value
report(c("big"))
#> x: 1 entry, such as big (n = 1) (0 missing)

# Single unique value repeated multiple times
report(c("big", "big", "big", "big"))
#> x: 1 entry, such as big (n = 4) (0 missing)

Testing

Added comprehensive test coverage in test-report_basic_methods.R for:

• Single unique character value
• Single unique value repeated multiple times
• Single unique value in data frame context

All existing tests continue to pass.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[Bug]: report fails when a character vector has only one unique value</issue_title>
<issue_description>### Describe the bug

report fails when a character vector has only one unique value with

Error in names(n_char) <- c("Entry", "n_Entry") :
'names' attribute [2] must be the same length as the vector [1]

Reproducible example

library(report)
packageVersion("report")
single_char_vector <- c("big")
df <- data.frame("id" = 1:6, "size" = single_char_vector)
report(df)

Session Info

R version 4.5.1 (2025-06-13 ucrt)
Platform: x86_64-w64-mingw32/x64
Running under: Windows 11 x64 (build 26100)

Matrix products: default
LAPACK version 3.12.1

locale:

[1] LC_COLLATE=Welsh_United Kingdom.utf8 LC_CTYPE=Welsh_United Kingdom.utf8
[3] LC_MONETARY=Welsh_United Kingdom.utf8 LC_NUMERIC=C
[5] LC_TIME=Welsh_United Kingdom.utf8

time zone: Europe/London
tzcode source: internal

attached base packages:
[1] stats graphics grDevices utils datasets methods base

other attached packages:
[1] report_0.6.1

loaded via a namespace (and not attached):
[1] compiler_4.5.1 tools_4.5.1 datawizard_1.2.0 rstudioapi_0.17.1 insight_1.4.2 </issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #578

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