Find blank cells (even hidden ones) and fill them in or remove them.

Tip: files imported on the Home screen are picked up here automatically.

Import CSV or Excel file

Preview: survey_responses.csv

2,150 rows, 6 columns

	respondent_id	age	region	income	satisfaction	comments
0	R-1001	34	West	52000	4	great service
1	R-1002	N/A	East		3	?
2	R-1003	41	-	61000	NULL	none
3	R-1004	29	South	N/A	5	quick

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Options

Missingness profile

Rows

2,150

Cells missing

1,043

% cells missing

8.1%

Complete rows

1,388

column	dtype	missing	missing_pct	disguised	has_missing
respondent_id	object	0	0.0%	0	False
age	float64	187	8.7%	61	True
region	object	142	6.6%	142	True
income	float64	329	15.3%	118	True
satisfaction	float64	95	4.4%	40	True
comments	object	290	13.5%	290	True

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Strategy

Preset

detect-only (standardize sentinels to NaN, no fill or drop) safe-fill (numeric → median, categorical → mode) drop-incomplete (drop any row with missing)

detect-only: replace 'N/A', '-', 'NULL', etc. with real NaN, then stop. safe-fill: also fill — numeric columns with median, others with mode. drop-incomplete: also drop every row that has any missing cell.

Advanced options

Detection

check Standardize disguised nulls to NaN

Sentinel values (comma-separated)

N/A, n/a, NA, NULL, null, None, -, --, ?, #N/A

Matched case-insensitively after stripping whitespace.

Strategy override

Global strategy

(use preset)

drop_row / drop_col use the thresholds below. mean / median / interpolate are numeric only — non-numeric columns fall back to the categorical strategy.

Categorical fallback (for non-numeric columns)

mode

Drop thresholds

Row drop threshold (drop rows with ≥ this fraction missing across selected cols)

1.00

Column drop threshold (drop columns with ≥ this fraction missing)

1.00

Scope

Columns to handle (default: all)

respondent_id ✕ age ✕ region ✕ income ✕ satisfaction ✕ comments ✕

Columns to skip

Choose columns

Per-column strategy overrides (optional)

Set a different strategy for specific columns. Leave any row blank to use the global strategy.

Column	Override
age	median
region	mode
income
satisfaction
comments	constant

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Handle Missing Values

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Results

Missingness — before vs. after

Strategy applied per column

Audit (first 50 changes)

… and 1,037 more (download the full audit below).

Handled preview (first 10 rows)

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