Export Table to HTML Format

Converts a data frame, data.table, or matrix to HTML format with optional CSS styling for web display, HTML documents, or embedding in web applications. Generates clean, standards-compliant HTML with professional styling options including responsive design support, color schemes, and interactive features. Requires xtable for export.

Usage

table2html(
  table,
  file,
  caption = NULL,
  format_headers = TRUE,
  variable_padding = FALSE,
  bold_significant = TRUE,
  bold_variables = FALSE,
  p_threshold = 0.05,
  indent_groups = FALSE,
  condense_table = FALSE,
  condense_quantitative = FALSE,
  zebra_stripes = FALSE,
  stripe_color = "#EEEEEE",
  dark_header = FALSE,
  include_css = TRUE,
  ...
)

Arguments

table: Data frame, data.table, or matrix to export. Can be output from desctable(), survtable(), fit(), uniscreen(), fullfit(), compfit(), multifit(), or any tabular data.
file: Character string specifying the output HTML filename. Must have .html or .htm extension. Example: "results.html".
caption: Character string. Optional caption displayed below the table. Supports basic HTML formatting. Default is NULL.
format_headers: Logical. If TRUE, formats column headers by converting underscores to spaces and applying proper casing. Wraps statistical notation ("n", "p") in <i> tags. Default is TRUE.
variable_padding: Logical. If TRUE, adds vertical spacing around variable groups for improved readability. Particularly useful for multi-row factor variables. Default is FALSE.
bold_significant: Logical. If TRUE, wraps significant p-values in <b> tags for bold display. Makes important results stand out visually. Default is TRUE.
bold_variables: Logical. If TRUE, variable names are displayed in bold. Default is FALSE.
p_threshold: Numeric. Threshold for bold p-value formatting. Only used when bold_significant = TRUE. Default is 0.05.
indent_groups: Logical. If TRUE, indents grouped rows using non-breaking spaces ( ) for hierarchical display. Useful for factor variables in regression output. Default is FALSE.
condense_table: Logical. If TRUE, condenses table by showing only essential rows. Automatically sets indent_groups = TRUE. Default is FALSE.
condense_quantitative: Logical. If TRUE, condenses continuous and survival variables into single rows while preserving all categorical variable rows (including binary). Only applies to descriptive tables from desctable(). Automatically sets indent_groups = TRUE. Unlike condense_table, this does not collapse binary categorical variables. Default is FALSE.
zebra_stripes: Logical. If TRUE, applies alternating background shading to different variables (not individual rows) for visual grouping. Default is FALSE.
stripe_color: Character string. HTML color specification for zebra stripes. Can use hex codes ("#EEEEEE"), RGB ("rgb(238,238,238)"), or color names ("lightgray"). Default is "#EEEEEE".
dark_header: Logical. If TRUE, creates black background with white text for the header row. Provides strong visual contrast. Default is FALSE.
include_css: Logical. If TRUE, includes embedded CSS styling in the output file for standalone HTML. Set to FALSE when embedding in existing HTML with its own stylesheet. Default is TRUE.
...: Additional arguments passed to xtable.

Value

Invisibly returns NULL. Creates an HTML file at the specified location that can be opened in web browsers or embedded in HTML documents.

Details

Output Format:

The function generates standards-compliant HTML5 markup with:

Semantic <table> structure
Proper <thead> and <tbody> sections
Accessible header cells (<th>)
Clean, readable markup
Optional embedded CSS styling

Standalone vs. Embedded:

Standalone HTML (include_css = TRUE):

Can be opened directly in web browsers
Includes all necessary styling
Self-contained, portable
Suitable for sharing via email or web hosting

Embedded HTML (include_css = FALSE):

For inclusion in existing HTML documents
No CSS included (use parent document's styles)
Smaller file size
Integrates with web frameworks (Shiny, R Markdown, Quarto)

CSS Styling:

When include_css = TRUE, the function applies professional styling:

Table: Border-collapse, sans-serif font (Arial), 20px margin
Cells: 8px vertical × 12px horizontal padding, left-aligned text
Borders: 1px solid #DDD (light gray)
Headers: Bold text, light gray background (#F2F2F2)
Numeric columns: Center-aligned (auto-detected)
Caption: Bold, 1.1em font, positioned below table

With dark_header = TRUE:

Header background: Black (#000000)
Header text: White (#FFFFFF)
Creates high contrast, modern appearance

With zebra_stripes = TRUE:

Alternating variable groups receive background color
Default color: #EEEEEE (light gray)
Applied via CSS class .zebra-stripe
Groups entire variable (all factor levels together)

Hierarchical Display:

The indent_groups option creates visual hierarchy using HTML non-breaking spaces:


<td><b>Treatment</b></td>  <!-- Variable name -->
<td>&nbsp;&nbsp;&nbsp;&nbsp;Control</td>  <!-- Indented level -->
<td>&nbsp;&nbsp;&nbsp;&nbsp;Active</td>   <!-- Indented level -->

Integration with R Markdown/Quarto:

For R Markdown or Quarto documents:


# Generate HTML fragment (no CSS)
table2html(results, "table.html", include_css = FALSE)

Then include in your document chunk with results='asis':


cat(readLines("table.html"), sep = "\n")

Or directly render without file:


# For inline display
htmltools::HTML(
  capture.output(
    print(xtable::xtable(results), type = "html")
  )
)

Integration with Shiny:

For Shiny applications:


# In server function
output$results_table <- renderUI({
  table2html(results_data(), "temp.html", include_css = FALSE)
  HTML(readLines("temp.html"))
})

# Or use directly with DT package for interactive tables
output$interactive_table <- DT::renderDT({
  results_data()
})

Accessibility:

The generated HTML follows accessibility best practices:

Semantic table structure
Proper header cells (<th>) with scope attributes
Clear visual hierarchy
Adequate color contrast (when using default styles)
Screen reader friendly markup

Examples

data(clintrial)
data(clintrial_labels)

# Create example table
results <- fit(
     data = clintrial,
     outcome = "os_status",
     predictors = c("age", "sex", "treatment", "stage"),
     labels = clintrial_labels
)

# Example 1: Basic HTML export (standalone)
if (requireNamespace("xtable", quietly = TRUE)) {
  table2html(results, file.path(tempdir(), "results.html"))
}
#> Table exported to /tmp/Rtmp9Tmfn9/results.html

# \donttest{
# Example 2: With caption
table2html(results, file.path(tempdir(), "captioned.html"),
          caption = "Table 1: Multivariable Logistic Regression Results")
#> Table exported to /tmp/Rtmp9Tmfn9/captioned.html

# Example 3: For embedding (no CSS)
table2html(results, file.path(tempdir(), "embed.html"),
          include_css = FALSE)
#> Table exported to /tmp/Rtmp9Tmfn9/embed.html
# Include in your HTML document

# Example 4: Hierarchical display
table2html(results, file.path(tempdir(), "indented.html"),
          indent_groups = TRUE)
#> Table exported to /tmp/Rtmp9Tmfn9/indented.html

# Example 5: Condensed table
table2html(results, file.path(tempdir(), "condensed.html"),
          condense_table = TRUE)
#> Table exported to /tmp/Rtmp9Tmfn9/condensed.html

# Example 6: With zebra stripes
table2html(results, file.path(tempdir(), "striped.html"),
          zebra_stripes = TRUE,
          stripe_color = "#F0F0F0")
#> Table exported to /tmp/Rtmp9Tmfn9/striped.html

# Example 7: Dark header style
table2html(results, file.path(tempdir(), "dark.html"),
          dark_header = TRUE)
#> Table exported to /tmp/Rtmp9Tmfn9/dark.html

# Example 8: Combination styling
table2html(results, file.path(tempdir(), "styled.html"),
          zebra_stripes = TRUE,
          dark_header = TRUE,
          bold_significant = TRUE)
#> Table exported to /tmp/Rtmp9Tmfn9/styled.html

# Example 9: Custom stripe color
table2html(results, file.path(tempdir(), "blue_stripes.html"),
          zebra_stripes = TRUE,
          stripe_color = "#E3F2FD")  # Light blue
#> Table exported to /tmp/Rtmp9Tmfn9/blue_stripes.html

# Example 10: Disable significance bolding
table2html(results, file.path(tempdir(), "no_bold.html"),
          bold_significant = FALSE)
#> Table exported to /tmp/Rtmp9Tmfn9/no_bold.html

# Example 11: Stricter significance threshold
table2html(results, file.path(tempdir(), "strict.html"),
          bold_significant = TRUE,
          p_threshold = 0.01)
#> Table exported to /tmp/Rtmp9Tmfn9/strict.html

# Example 12: No header formatting
table2html(results, file.path(tempdir(), "raw_headers.html"),
          format_headers = FALSE)
#> Table exported to /tmp/Rtmp9Tmfn9/raw_headers.html

# Example 13: Descriptive statistics table
desc_table <- desctable(clintrial, by = "treatment",
     variables = c("age", "sex", "bmi"), labels = clintrial_labels)

table2html(desc_table, file.path(tempdir(), "baseline.html"),
          caption = "Table 1: Baseline Characteristics by Treatment Group")
#> Table exported to /tmp/Rtmp9Tmfn9/baseline.html

# Example 14: For R Markdown (no CSS, for inline display)
table2html(results, file.path(tempdir(), "rmd_table.html"),
          include_css = FALSE,
          indent_groups = TRUE)
#> Table exported to /tmp/Rtmp9Tmfn9/rmd_table.html

# Then in R Markdown, use a chunk with results='asis' to display inline:
cat(readLines(file.path(tempdir(), "rmd_table.html")), sep = "\n")
#> <!-- html table generated in R 4.5.2 by xtable 1.8-4 package -->
#> <!-- Tue Mar  3 19:55:24 2026 -->
#> <table border=1>
#> <tr> <th> Variable </th> <th> <i>n</i> </th> <th> Events </th> <th> aOR (95% CI) </th> <th> <i>p</i>-value </th>  </tr>
#>   <tr> <td> Age (years) </td> <td> 847 </td> <td> 606 </td> <td> 1.05 (1.04-1.07) </td> <td> <b>< 0.001</b> </td> </tr>
#>   <tr> <td> Sex </td> <td>  </td> <td>  </td> <td>  </td> <td> - </td> </tr>
#>   <tr> <td> &nbsp;&nbsp;&nbsp;&nbsp;Female </td> <td> 449 </td> <td> 297 </td> <td> reference </td> <td>  </td> </tr>
#>   <tr> <td> &nbsp;&nbsp;&nbsp;&nbsp;Male </td> <td> 398 </td> <td> 309 </td> <td> 2.02 (1.45-2.82) </td> <td>  </td> </tr>
#>   <tr> <td> Treatment Group </td> <td>  </td> <td>  </td> <td>  </td> <td> - </td> </tr>
#>   <tr> <td> &nbsp;&nbsp;&nbsp;&nbsp;Control </td> <td> 194 </td> <td> 149 </td> <td> reference </td> <td>  </td> </tr>
#>   <tr> <td> &nbsp;&nbsp;&nbsp;&nbsp;Drug A </td> <td> 292 </td> <td> 184 </td> <td> 0.44 (0.28-0.68) </td> <td>  </td> </tr>
#>   <tr> <td> &nbsp;&nbsp;&nbsp;&nbsp;Drug B </td> <td> 361 </td> <td> 273 </td> <td> 0.74 (0.48-1.16) </td> <td>  </td> </tr>
#>   <tr> <td> Disease Stage </td> <td>  </td> <td>  </td> <td>  </td> <td> - </td> </tr>
#>   <tr> <td> &nbsp;&nbsp;&nbsp;&nbsp;I </td> <td> 211 </td> <td> 127 </td> <td> reference </td> <td>  </td> </tr>
#>   <tr> <td> &nbsp;&nbsp;&nbsp;&nbsp;II </td> <td> 263 </td> <td> 172 </td> <td> 1.32 (0.88-1.97) </td> <td>  </td> </tr>
#>   <tr> <td> &nbsp;&nbsp;&nbsp;&nbsp;III </td> <td> 241 </td> <td> 186 </td> <td> 2.70 (1.74-4.19) </td> <td>  </td> </tr>
#>   <tr> <td> &nbsp;&nbsp;&nbsp;&nbsp;IV </td> <td> 132 </td> <td> 121 </td> <td> 9.08 (4.49-18.37) </td> <td>  </td> </tr>
#>    </table>

# Example 15: Email-friendly version
table2html(results, file.path(tempdir(), "email.html"),
          include_css = TRUE,  # Self-contained
          zebra_stripes = TRUE,
          caption = "Regression Results - See Attached")
#> Table exported to /tmp/Rtmp9Tmfn9/email.html
# Can be directly included in HTML emails

# Example 16: Publication-ready web version
table2html(results, file.path(tempdir(), "publication.html"),
          caption = "Table 2: Multivariable Analysis of Risk Factors",
          indent_groups = TRUE,
          zebra_stripes = FALSE,  # Clean look
          bold_significant = TRUE,
          dark_header = FALSE)
#> Table exported to /tmp/Rtmp9Tmfn9/publication.html

# Example 17: Modern dark theme
table2html(results, file.path(tempdir(), "dark_theme.html"),
          dark_header = TRUE,
          stripe_color = "#2A2A2A",  # Dark gray stripes
          zebra_stripes = TRUE)
#> Table exported to /tmp/Rtmp9Tmfn9/dark_theme.html

# Example 18: Minimal styling for custom CSS
table2html(results, file.path(tempdir(), "minimal.html"),
          include_css = FALSE,
          format_headers = FALSE,
          bold_significant = FALSE)
#> Table exported to /tmp/Rtmp9Tmfn9/minimal.html
# Apply your own CSS classes and styling

# Example 19: Model comparison table
models <- list(
     base = c("age", "sex"),
     full = c("age", "sex", "treatment", "stage")
)

comparison <- compfit(
     data = clintrial,
     outcome = "os_status",
     model_list = models
)
#> Auto-detected binary outcome, using logistic regression
#> Fitting base with 2 predictors...
#> Fitting full with 4 predictors...

table2html(comparison, file.path(tempdir(), "comparison.html"),
          caption = "Model Comparison Statistics")
#> Table exported to /tmp/Rtmp9Tmfn9/comparison.html

# }

Usage

Arguments

Value

Details

See also

Examples