Using the datefixR Shiny App

Introduction

The datefixR package provides a user-friendly Shiny app that allows users to standardize messy date data using a graphical user interface (GUI). This is particularly useful for researchers, data analysts, and anyone working with datasets containing inconsistently formatted dates who prefer not to use R code directly.

The app supports the same powerful date parsing capabilities as the core datefixR functions, including:

Multiple date formats and separators
International month names in 9 languages
Custom imputation strategies for missing date components
Excel and CSV file processing
Batch processing of multiple date columns

Installation and Setup

Prerequisites

The Shiny app requires additional dependencies that are not installed automatically with datefixR. This design choice allows the core package to be installed on secure systems where these packages might not be permitted.

Required dependencies: - DT - for interactive data tables - shiny - for the web application framework - readxl - for reading Excel files - htmltools - for HTML generation

Launching the App

To start the app, simply run:

fix_date_app()

If any required dependencies are missing, the app will detect this and offer to install them automatically.

Theme Options

The app supports two visual themes:

# Default datefixR theme (recommended)
fix_date_app(theme = "datefixR")

# Standard Shiny theme
fix_date_app(theme = "none")

Step-by-Step Usage Guide

1. File Upload

Click the Browse button in the left sidebar
Select either a CSV (.csv) or Excel (.xlsx) file
The file will be automatically uploaded and processed
Click Refresh to display the uploaded data

2. Column Selection

After uploading your file:

Review the data in the Results tab
In the left sidebar, check boxes will appear for each column
Select the columns containing date data that need to be standardized
Multiple columns can be selected simultaneously

3. Imputation Settings

Configure how missing date components should be handled:

Day of Month Imputation

Options: 1-28, or NA
Default: 1 (first day of month)
Purpose: What day to use when only month/year are provided

Month Imputation

Options: 1-12, or NA
Default: 7 (July)
Purpose: What month to use when only year is provided

Format Assumption

Options: “dmy” (day-month-year) or “mdy” (month-day-year)
Default: “dmy”
Purpose: How to interpret ambiguous numeric dates like “01/02/2023”

4. Processing and Review

Click Refresh after selecting columns and setting preferences
The processed data will appear in the Results tab
Review the standardized dates to ensure they meet your expectations
All date columns will now be in YYYY-MM-DD format

5. Download Results

Click the Download button to save your processed data
The file will be saved as “fixed.csv”
All selected date columns will be standardized in the output

Advanced Features

File Format Support

The app automatically detects and handles:

CSV files: Comma-separated values with automatic encoding detection
Excel files: Both .xlsx and .xls formats, reads the first worksheet

Error Handling

If the app encounters problematic dates:

Error messages will appear in the R console
The problematic row and date value will be identified
Processing will stop, allowing you to review and correct the data

Data Privacy

Important Security Note: When using online hosting platforms (like shinyapps.io), your uploaded files are temporarily stored on the hosting platform’s servers. While no data should be stored persistently, use discretion with sensitive data. For maximum security, run the app locally.

Example Workflow

Here’s a complete example of using the app:

Prepare your data: Create a CSV file with messy dates

id,event_date,follow_up
1,"02/03/21","April 2021"
2,"15-Dec-2020","2021"
3,"2020/05/01","May 15 2021"

Launch and configure:
```
fix_date_app()
```
Upload and process:
- Upload your CSV file
- Select “event_date” and “follow_up” columns
- Set day imputation to 15, month imputation to 6
- Click Refresh
Download results: Clean, standardized date data ready for analysis

Troubleshooting

Common Issues

App won’t start: - Ensure all dependencies are installed - Try running install.packages(c("DT", "shiny", "readxl", "htmltools"))

File won’t upload: - Check file format (only .csv and .xlsx supported) - Ensure file size is reasonable (< 100MB recommended) - Verify file isn’t corrupted

Dates not parsing correctly: - Review your format assumption (dmy vs mdy) - Check for unusual date formats in your data - Consider pre-cleaning obviously problematic entries

Download not working: - Ensure you’ve selected at least one date column - Try refreshing the processed data first - Check browser download settings

Performance Considerations

File Size: The app handles files up to several thousand rows efficiently
Processing Time: Complex date parsing may take a few seconds for large datasets
Memory Usage: Keep file sizes reasonable (< 100MB) for optimal performance

For the latest updates and to report issues, visit the datefixR GitHub repository.