Adding Columns

VisiData gives you several ways to add new columns. The most common: za for a blank column, = for a computed column, i for a row-number column. On this server, the common-config also adds Space rn Enter for a leftmost no row-number column.

Learning Focus

Use za when you just need a new empty column (like a tag column). Use = when you want a computed value. Use i for built-in row numbering. Use Space rn Enter when you specifically want the column named no placed at the far left.

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Add a Blank Column (za)

This is the primary way to add a new empty column — equivalent to inserting a column in Excel.

za          # add one blank column
gza N       # add N blank columns

Example — add a tag column for manual annotation:

za
# Enter column name: tag

All cells in the new column are empty. Edit them with e.

Example — add 3 blank columns at once:

gza 3
# Enter name prefix: extra
# Creates: extra_1, extra_2, extra_3

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Add an Incremental Column (i, zi)

Add a column with sequential integers — useful for row numbering.

i           # add new column with 1, 2, 3...
zi step     # add new column with custom step

# Add a row ID
i
# Enter name: row_id
# Result: 1, 2, 3, 4, ...

# Add a column with step of 100
zi 100
# Enter name: batch
# Result: 100, 200, 300, ...

For filling existing columns with incremental values (gi, gzi), see Column Editing.

Custom Leftmost Row Number Column (Space rn Enter)

The common-config VisiData setup provides a custom command named rn:

Space rn Enter

Result:

no | existing_col_1 | existing_col_2 | ...
1  | ...            | ...            | ...
2  | ...            | ...            | ...
3  | ...            | ...            | ...

Use rn when you want a standard row-number column for export, auditing, screenshots, or talking through rows with someone else.

Key differences:

Command	Result
i	Adds an incremental column using VisiData's built-in command
gi	Fills the current selected rows in the current column
Space rn Enter	Adds a new first column named no and fills all rows from 1 to N

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Add a Derived Column (=)

Press = to add a new column computed from a Python expression. Column names become variables in the expression.

=           # create a new derived column from Python expression

# 10% bonus on salary
=
# Enter: salary * 0.10
# Enter column name: bonus

# Full name from first + last
=
# Enter: first_name + ' ' + last_name
# Enter column name: full_name

# Classification by salary tier
=
# Enter: 'senior' if salary > 80000 else 'mid' if salary > 50000 else 'junior'

# Create a blank tag column (no expression needed)
=
# Enter: ""
# Enter column name: tag

Expression rules:

• Simple names: salary, name, region
• Names with spaces: row['column name']
• System variable: rownum (0-based row index)

Derived columns are ephemeral — they recompute every time the source data changes. Export the sheet to save them permanently.

For detailed Python expression patterns, see Formulas and Calculations.

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Duplicate a Column (Y + gP)

Copy an existing column and paste it as a new column — no expression or regex needed.

Shift+C     # open Columns Sheet
# Move to the column row you want to duplicate
Y           # yank (copy) the column row
gP          # paste it as a new column at the bottom
K           # move it into position (up)

Then rename with ^ and edit values as needed. See Columns Sheet Operations for details.

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Quick Comparison

Need	Use	Key
Empty column for manual entry	za	za
Row numbers	i / zi	i
Leftmost no row-number column	custom common-config command	Space rn Enter
Computed value	=	=
Copy of existing column	Y + gP	Columns Sheet

Quick Reference

Key	Action	Python?
za	Add one blank column	No
gza N	Add N blank columns	No
i	Sequential integers 1, 2, 3...	No
zi N	Sequential with custom step	No
Space rn Enter	Add leftmost no sequence column	No
= expr	Derived column from Python	Yes
Y + gP	Duplicate column (Columns Sheet)	No

Hands-On Practice

vd ~/github/practice-folder/visidata/01-loading/01-employees.csv

# 1. za → tag → creates a blank 'tag' column
# 2. Move to a tag cell → e → type "urgent" → Enter
# 3. i → row_id → creates a 1,2,3... row number column
# 4. Space rn Enter → creates a leftmost no column
# 5. = → salary * 1.10 → bonus → creates a computed bonus column

What's Next

• Column Editing — modify existing column values in-place
• Splitting and Extracting — split a column into multiple new columns