# Replace values Shape / columns replace or map values, find and replace, value mapper Page: ## Status Runs as a SQL step. arcform carries it as a `sql:` step today. ## The DuckDB step map values through a lookup It reads the `orders` table the proofs share. Create it first: ```sql CREATE TABLE orders AS SELECT * FROM (VALUES (1, 'Alice Ng', 'north', DATE '2026-01-03', 120.00, 'widget', 'a|b', '{"channel":"web","items":[1,2]}'), (2, 'alice ng', 'north', DATE '2026-01-05', 80.50, 'gadget', 'b', '{"channel":"shop","items":[3]}'), (3, 'Bob Okafor', 'south', DATE '2026-01-05', 300.00, 'widget', 'a|c', '{"channel":"web","items":[4,5,6]}'), (4, 'Carla Díaz', 'east', DATE '2026-01-09', NULL, 'gizmo', NULL, '{"channel":"web","items":[]}'), (5, 'Bob Okafor', 'south', DATE '2026-01-12', 45.25, 'gadget', 'c', '{"channel":"phone","items":[7]}'), (6, 'Dev Patel', 'west', DATE '2026-01-12', 510.00, 'widget', 'a', '{"channel":"web","items":[8,9]}'), (7, 'Carla Diaz', 'east', DATE '2026-01-20', 99.99, 'gizmo', 'b|c', '{"channel":"shop","items":[10]}'), (8, 'Dev Patel', 'west', DATE '2026-02-02', 510.00, 'widget', 'a', '{"channel":"web","items":[8,9]}'), (9, 'Eve Larsen', NULL, DATE '2026-02-03', 15.00, 'gadget', NULL, '{"channel":"web","items":[11]}'), (10, 'Alice Ng', 'north', DATE '2026-02-10', 220.00, 'gizmo', 'a|b|c', '{"channel":"phone","items":[12,13]}') ) t(order_id, customer, region, order_date, amount, product, tags, meta); ``` Then run the statement: ```sql CREATE TEMP TABLE result AS SELECT order_id, region, coalesce(MAP {'north':'N','south':'S','east':'E','west':'W'}[region], '?') AS region_code FROM orders; SELECT * FROM result; SELECT CASE WHEN ((SELECT count(*) FILTER (WHERE region_code = '?') = 1 AND count(*) FILTER (WHERE region = 'north' AND region_code = 'N') = 3 FROM result)) THEN 'as expected' ELSE error('the lookup did not code north as N and the missing region as ?') END AS verdict; ``` It needs nothing installed beyond DuckDB itself. ## Variants - Replace errors, infinities and invalid values: Replace error values, infinities, values that do not fit the column type, or chosen values with null. - Map given values to new ones: Replace whole cell values that match given values with new values, leaving the rest or using a default. - [Replace values from a mapping table](https://meridian.online/operations/replace-values/replace-values-from-a-mapping-table): Take the pairs of old and new values from a second table and apply them to one or more columns. - Group rare or unseen values: Replace infrequent values, or values not seen in training, with one placeholder. - [Find and replace text inside values](https://meridian.online/operations/replace-values/find-and-replace-text-inside-values): Replace a substring or pattern wherever it occurs inside a text value. ## What other tools call it Meridian's classification; an independent blind rating agreed on 86.2% of 312 rows (exact class, version 2). - Alteryx Designer: [`Dynamic Replace`](https://help.alteryx.com/current/en/designer/tools/developer/dynamic-replace-tool.html) (read 2026-09-27) - Duckle: [`Replace (literal)`](https://github.com/slothflowlabs/duckle/blob/f85f8960edfb6efbf4cb89d58a7b32e16df0e867/frontend/src/workflow-ui/palette-data.ts) (read 2026-09-25) - EasyMorph: [`Clean up`](https://help.easymorph.com/doku.php?id=transformations:cleanup) (read 2026-09-27) - EasyMorph: [`Group`](https://help.easymorph.com/doku.php?id=transformations:group) (read 2026-09-27) - EasyMorph: [`Replace`](https://help.easymorph.com/doku.php?id=transformations:replace) (read 2026-09-27) - EasyMorph: [`Replace with lookup`](https://help.easymorph.com/doku.php?id=transformations:replacewithlookup) (read 2026-09-27) - EasyMorph: [`Table-wide replace`](https://help.easymorph.com/doku.php?id=transformations:massreplace) (read 2026-09-27) - Apache Hop: [`Replace in String`](https://hop.apache.org/manual/latest/pipeline/transforms/replacestring.html) (read 2026-09-27) - Apache Hop: [`Token replacement`](https://hop.apache.org/manual/latest/pipeline/transforms/tokenreplacement.html) (read 2026-09-27) - Apache Hop: [`Value Mapper`](https://hop.apache.org/manual/latest/pipeline/transforms/valuemapper.html) (read 2026-09-27) - Ibis: [`StringReplace`](https://github.com/ibis-project/ibis/blob/05d2b293344e86cb41c1a426071734f7e270335a/ibis/expr/operations/strings.py) (read 2026-09-27) - KNIME Analytics Platform: [`String Replacer`](https://api.hub.knime.com/nodes/*kg6wiYxLaACvn7qm?details=full) (read 2026-09-27) - KNIME Analytics Platform: [`String Replacer (Dictionary)`](https://api.hub.knime.com/nodes/*yEWV69hLfijLvmTJ?details=full) (read 2026-09-27) - Apache NiFi: [`ReplaceTextWithMapping`](https://nifi.apache.org/components/org.apache.nifi.processors.standard.ReplaceTextWithMapping/) (read 2026-09-27) - OpenRefine: [`Replace…`](https://openrefine.org/docs/manual/cellediting#replace) (read 2026-09-27) - Pentaho Data Integration: [`Replace in String`](https://docs.pentaho.com/pdia-data-integration/9.3-data-integration/pdi-transformation-steps-reference-overview) (read 2026-09-27) - Pentaho Data Integration: [`Value Mapper`](https://docs.pentaho.com/pdia-data-integration/9.3-data-integration/pdi-transformation-steps-reference-overview) (read 2026-09-27) - Polars: [`Expr.replace`](https://docs.pola.rs/api/python/stable/reference/expressions/modify_select.html) (read 2026-09-27) - Polars: [`Expr.replace_strict`](https://docs.pola.rs/api/python/stable/reference/expressions/modify_select.html) (read 2026-09-27) - Power Query M: [`Replacer functions`](https://learn.microsoft.com/en-us/powerquery-m/replacer-functions) (read 2026-09-27) - Power Query M: [`Table.ReplaceErrorValues`](https://learn.microsoft.com/en-us/powerquery-m/table-functions#transformation) (read 2026-09-27) - Power Query M: [`Table.ReplaceValue`](https://learn.microsoft.com/en-us/powerquery-m/table-functions#transformation) (read 2026-09-27) - RapidMiner Studio: [`Handle Unknown Values`](https://docs.rapidminer.com/latest/studio/operators/cleansing/missing/handle_unknown_values.html) (read 2026-09-27) - RapidMiner Studio: [`Map`](https://docs.rapidminer.com/latest/studio/operators/blending/values/map.html) (read 2026-09-27) - RapidMiner Studio: [`Merge`](https://docs.rapidminer.com/latest/studio/operators/blending/values/merge.html) (read 2026-09-27) - RapidMiner Studio: [`Replace Infinite Values`](https://docs.rapidminer.com/latest/studio/operators/cleansing/missing/replace_infinite_values.html) (read 2026-09-27) - RapidMiner Studio: [`Replace Rare Values`](https://docs.rapidminer.com/latest/studio/operators/extensions/Operator%20Toolbox/blending/replace_rare.html) (read 2026-09-27) - Apache SeaTunnel: [`Replace`](https://seatunnel.apache.org/docs/2.3.13/transforms/replace) (read 2026-09-27) - Tableau Prep: [`Manual Selection`](https://help.tableau.com/current/prep/en-us/prep_clean.htm) (read 2026-09-27) - Tableau Prep: [`Replace with Null`](https://help.tableau.com/current/prep/en-us/prep_clean.htm) (read 2026-09-27) - Talend: [`tReplace`](https://help.qlik.com/talend/en-US/components/8.0/processing/processing-component) (read 2026-09-27) - Talend: [`tReplaceList`](https://help.qlik.com/talend/en-US/components/8.0/standardization/standardization-component) (read 2026-09-27) - Trifacta: [`Convert patterns`](https://help.alteryx.com/aac/en/trifacta-classic/reference/transformation-reference.html) (read 2026-09-27) - Trifacta: [`Replace Transform`](https://help.alteryx.com/aac/en/trifacta-classic/wrangle-language/language-appendices/transforms.html) (read 2026-09-27) - Trifacta: [`Replace between delimiters`](https://help.alteryx.com/aac/en/trifacta-classic/reference/transformation-reference.html) (read 2026-09-27) - Trifacta: [`Replace between positions`](https://help.alteryx.com/aac/en/trifacta-classic/reference/transformation-reference.html) (read 2026-09-27) - Trifacta: [`Replace cells`](https://help.alteryx.com/aac/en/trifacta-classic/reference/transformation-reference.html) (read 2026-09-27) - Trifacta: [`Replace mismatched`](https://help.alteryx.com/aac/en/trifacta-classic/reference/transformation-reference.html) (read 2026-09-27) - Trifacta: [`Replace text or pattern`](https://help.alteryx.com/aac/en/trifacta-classic/reference/transformation-reference.html) (read 2026-09-27)