Data cleaning

Fix duplicates, extra spaces, numbers and dates stored as text, joined columns and blank cells in imported data.

10 lessons · about 1 h 45 min · 1 free · Confident to Advanced

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Lessons

In the order the Roadmap teaches them. The free one needs no sign-up.

Free · Confident · 9 min

Remove duplicates

Delete repeated rows from a merged list, and choose which columns decide what counts as a duplicate.

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In the full course. Confident · 8 min

Split one column into several

Split text that arrived in one column into separate columns at a comma, semicolon or any other separator, without losing data to the right.

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In the full course. Confident · 9 min

Fix numbers stored as text

Spot numbers that are stored as text, turn them into real numbers with VALUE, and paste the fixed values over the originals.

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In the full course. Confident · 12 min

Fix dates stored as text

Spot dates stored as text, turn them into real dates with DATEVALUE, and rebuild any other layout with DATE, LEFT, MID and RIGHT.

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In the full course. Confident · 10 min

Remove hidden characters and extra spaces

Find the characters TRIM can't remove, such as non-breaking spaces and line breaks, and clean them with SUBSTITUTE, CLEAN and TRIM in one formula.

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In the full course. Confident · 10 min

Fill blank cells with the value above

Fill the empty cells in a list so every row shows its group's name. You will use a helper column and paste values.

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In the full course. Confident · 11 min

Standardize inconsistent entries ("NY" vs "New York")

Make every version of a value, like NY, N.Y. and New York, read the same with Find and replace or a mapping table, so totals and counts add up.

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In the full course. Confident · 12 min

Clean an imported CSV

Take a messy export from another app and fix its usual problems in order, with Remove duplicates, Split text, TRIM, VALUE and DATEVALUE.

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In the full course. Confident · 14 min

Project: clean a messy customer list

Turn a customer list merged from two sources into one clean row per customer, with tidy names and emails, standard state codes and no repeats.

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In the full course. Advanced · 12 min

Reshape data from wide to long

Turn a grid with months across the top into a list with one row per item and month, using TOCOL, SEQUENCE and INDEX.

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Clean up messy data

For exports, CSVs and form responses that need tidying before anyone can use them.

10 lessons · about 1 h 30 min · 1 free · Beginner to Confident

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