CSV Explorer — User Guide

Top Menu Bar

File Operations

• New Empty File: Start with a blank single-column table.
• File → Upload File: Pick a CSV from your device. Set the delimiter first if it isn't a comma. Large files trigger a size warning with sampling options.
• File → Export File: Download the current table as a CSV. Edit the file name inline before exporting.
• Clear: Remove all data and reset the workspace.

Browser Storage

• Storage → Save: Save the current dataset (data, column order, filters, hidden columns, metadata) to your browser's IndexedDB.
• Storage → Load Saved: Restore a previously saved dataset without re-uploading the file.

Actions Dropdown

The Actions dropdown appears when data is loaded. It contains dataset-wide and selection-based operations that don't depend on a specific right-clicked column or row.

• Show All Hidden Columns: Reveal every hidden column. Visible when hidden columns exist.
• Reduce to Filtered Data: Permanently keep only the visible (filtered) rows and clear all filters. Disabled during sample mode.
• Chart vs Other Columns: Open the multi-column chart picker to explore relationships between columns.
• Extract Selected Columns: Keep only the selected columns; remove the rest. Visible when columns are selected.
• Extract Selected Rows: Keep only the selected rows; remove the rest (hidden/filtered rows are always preserved). Visible when rows are selected.
• Delete Selected Columns: Remove all selected columns at once. Visible when columns are selected.
• Delete Selected Rows: Remove all selected rows at once (hidden/filtered rows are always preserved). Visible when rows are selected.
• Unselect All: Clear both column and row selections at once. Visible when both columns and rows are selected.
• Unselect All Columns: Clear all column selections at once. Visible when columns are selected.
• Unselect All Rows: Clear all row selections at once. Visible when rows are selected.
• Concatenate Selected Columns: Merge selected columns into a new column with a custom separator. Disabled during sample mode. Requires at least 2 columns selected.

Other Controls

• Delimiter: The character used to separate values when uploading. Default is comma. Change it before loading a file.
• Page Selector: Appears when data exceeds 500 rows. Navigate between pages.
• Dark / Light Mode: Toggle in the top-right corner. Preference is remembered across sessions.
• File Name: Click the file name in the center of the menu bar to rename it.

Sample Isolation Mode

Create a random sample and work on it in a sandbox. Sort, filter, delete, replace — everything operates on the sample only. When you're done, accept or reject the result.

• Sample → Sample Rows...: Enter the number of rows. A random subset is extracted and the full dataset is saved as a snapshot in the background.
• Sample → Accept Sample: Discard the original data and keep the (possibly modified) sample as your new dataset. Row numbers are regenerated sequentially.
• Sample → Reject Sample: Throw away all changes made during sampling and restore the original dataset exactly as it was.

While in sample mode a badge shows "Sample: N of M rows" and the Sample button turns orange. Some actions are disabled to prevent conflicts: New Empty File, Upload File, Storage, Clear, Reduce to Filtered Data, and Concatenate Selected Columns.

Large File Handling

Files over 5 MB trigger a warning dialog with options:

• Proceed Anyway: Load the full file (may be slow on large files).
• Random Sample: Load a statistically representative subset.
• Top Rows: Load the first N rows for quick inspection.
• Custom Size: Choose exactly how many rows to load.

Limits: 10 MB on mobile, 50 MB on desktop. Memory usage is roughly 3× the file size.

Working with the Table

Editing

• Edit a cell: Double-click it. Press Enter to confirm, Escape to cancel.
• Rename a column: Double-click the column header. Same keyboard shortcuts apply.

Reordering Columns

• Grab the drag handle (⠇) on any column header and drop it at a new position.

Column Types

• Each column is auto-detected as numerical or categorical (samples 100 values, >80% numeric = numerical).
• Type badges appear below column headers: NUM (blue) or CAT (green).
• You can override the type via the action menu (Convert to Categorical / Convert to Numerical).

Opening the Action Menu

• Click the dropdown arrow (▼) next to any column header or row number. The arrow turns red when a filter or selection is active.
• The action menu groups all available operations. Use the search bar at the top to find an action quickly.

Action Menu Reference

Actions are context-aware — they appear or hide based on whether you clicked a column header, a row, or have an active selection.

Select & Deselect

• Select / Unselect Column: Toggle the clicked column.
• Select / Unselect All Columns: Toggle all visible columns at once.
• Select / Unselect Row: Toggle the clicked row.
• Select / Unselect All Rows On Page: Toggle all rows on the current page.
• Hide Column: Remove a column from view without deleting it.

Insert

• Add Column (Left / Right): Insert an empty column next to the clicked one.
• Add Row (Up / Down): Insert a blank row above or below the clicked one.

Sort

• Sort Ascending / Descending: Sort by the clicked column. Respects column type (numeric vs. alphabetical).

Filter & Clean

• Filter Column: Opens a modal listing every unique value. Toggle values on/off, search through them, or use Hide All / Show All.
• Replace Values: Find and replace text within a column.
• Remove Duplicates: Keep the first occurrence of each value; remove later duplicates (visible rows only).
• Drop Missing Values: Delete rows where the column is empty or null (visible rows only).

Analyze & Group

• Describe Column: Shows count, unique count, min, max, mean, median, standard deviation, and more. Stats can be exported as CSV.
• Show Value Counts: Frequency table of each unique value (categorical columns only).
• Group & Aggregate: Group rows by the clicked column and pick an aggregation for each other column: Count, Count Unique, Sum, Mean, Median, Min, Max, Std Dev, Top Value, First/Last Value, or Collect Array.
• Convert to Categorical / Numerical: Override the auto-detected column type.

Extract & Delete

• Explode Column by Delimiter: Split a column into multiple columns by a delimiter (e.g., split "hello_world" by "_"). Auto-detects the number of output columns with a live preview. Optionally keep the original.
• Delete Column / Row: Remove the clicked column or row.

Visualize

• Chart This Column: Create a single-column chart. The app recommends a chart type based on the column type.

Charts & Visualization

Single-Column Charts

• Numerical: Histogram, Box Plot, Summary Stats.
• Categorical: Bar Chart, Pie Chart, Donut Chart.

Multi-Column Charts

• Num vs Num: Scatter Plot, Line Chart, Bubble Chart.
• Cat vs Num: Bar Chart, Box Plot, Violin Plot.
• Num vs Cat: Grouped Histogram, Density Plot.
• Cat vs Cat: Heatmap, Stacked Bar, Grouped Bar.

Customization & Export

• Add titles, axis labels, and legends from the configuration panel.
• Color-group scatter/line/bar charts by a third column.
• Export any chart as PNG (raster) or SVG (vector).

Tips

• Use Sample Isolation Mode to experiment safely — you can always reject and go back.
• Set the delimiter before uploading a file (semicolons, tabs, pipes, etc.).
• Hidden rows (from filters) are preserved during delete and extract operations — only visible rows are affected.
• There is no undo. Export your data or use Sample Mode before making destructive changes.
• All data stays in your browser. Nothing is uploaded anywhere.