Read an Excel file and return its contents as a string.

Args:
    file_path: Path to the Excel file
    sheet_name: Name of the sheet to read (only for .xlsx, .xls)
    nrows: Maximum number of rows to read
    header: Row to use as header (0-indexed)
    
Returns:
    String representation of the Excel data

Write data to an Excel file.

Args:
    file_path: Path to save the Excel file
    data: Data in CSV or JSON format
    sheet_name: Name of the sheet (for Excel files)
    format: Format of the input data ('csv' or 'json')
    
Returns:
    Confirmation message

Update an existing Excel file with new data.

Args:
    file_path: Path to the Excel file to update
    data: New data in CSV or JSON format
    sheet_name: Name of the sheet to update (for Excel files)
    format: Format of the input data ('csv' or 'json')
    
Returns:
    Confirmation message

Perform statistical analysis on Excel data.

Args:
    file_path: Path to the Excel file
    columns: Comma-separated list of columns to analyze (analyzes all numeric columns if None)
    sheet_name: Name of the sheet to analyze (for Excel files)
    
Returns:
    JSON string with statistical analysis

Filter Excel data using a pandas query string.

Args:
    file_path: Path to the Excel file
    query: Pandas query string (e.g., "Age > 30 and Department == 'Sales'")
    sheet_name: Name of the sheet to filter (for Excel files)
    
Returns:
    Filtered data as string

Create a pivot table from Excel data.

Args:
    file_path: Path to the Excel file
    index: Column to use as the pivot table index
    columns: Optional column to use as the pivot table columns
    values: Column to use as the pivot table values
    aggfunc: Aggregation function ('mean', 'sum', 'count', etc.)
    sheet_name: Name of the sheet to pivot (for Excel files)
    
Returns:
    Pivot table as string

Create a chart from Excel data and return as an image.

Args:
    file_path: Path to the Excel file
    x_column: Column to use for x-axis
    y_column: Column to use for y-axis
    chart_type: Type of chart ('line', 'bar', 'scatter', 'hist')
    sheet_name: Name of the sheet to chart (for Excel files)
    
Returns:
    Chart as image

Generate a comprehensive summary of the data in an Excel file.

Args:
    file_path: Path to the Excel file
    sheet_name: Name of the sheet to summarize (for Excel files)
    
Returns:
    Comprehensive data summary as string