add_header_row produced an error after using delete_column()

[ifendo]

Hi,

Thank you for developing the flextable package.

For my use case, I need to dynamically remove a column using the delete_columns() function and then add a custom header row with column spans to the resulting table. However, I am encountering issues when attempting this. Here's a minimal reproducible example:

library(flextable)

# Sample data
df <- data.frame(
  a = c(1, 2, 3),
  b = c(4, 5, 6),
  c = c(7, 8, 9)
)

# Create flextable
df_flex <- df |> flextable::flextable()

# Delete a column
df2 <- df_flex |> flextable::delete_columns("b")

# Add a column span header, it produced an error
df2 <- df2 |> flextable::add_header_row(values = c("x"), colwidths = 2)

I would like to know:

• Is it possible to add a header row with column spans after deleting a column?
• If not, is there a recommended workaround to achieve this behavior?

Thank you for your time and support!

[ifendo]

and attached my session info for reference:

R version 4.2.3 (2023-03-15)
Platform: aarch64-apple-darwin20 (64-bit)
Running under: macOS 14.7.4

Matrix products: default
LAPACK: /Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/lib/libRlapack.dylib

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

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

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.10             knitr_1.48              fontquiver_0.2.1        xml2_1.3.4              uuid_1.1-0              R6_2.5.1                ragg_1.2.5              rlang_1.1.0            
 [9] fastmap_1.2.0           fontBitstreamVera_0.1.1 highr_0.11              tools_4.2.3             grid_4.2.3              data.table_1.14.8       xfun_0.48               cli_3.6.1              
[17] htmltools_0.5.8.1       systemfonts_1.1.0       askpass_1.1             openssl_2.0.6           digest_0.6.31           lifecycle_1.0.3         textshaping_0.3.6       zip_2.3.0              
[25] officer_0.6.7.005       evaluate_0.21           flextable_0.9.8.003     rmarkdown_2.28          compiler_4.2.3          gdtools_0.4.1           fontLiberation_0.1.0   

[ifendo]

after deleting the b column using delete_columns(), I noticed we have:

I felt like df2$header$dataset is not expected(it did not delete column b), but I am not quite sure thought. Thank you.