Exercise 12 of 17

Regex filter and a computed column

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For sequences whose division matches the regular expression 'Basel.*', return the strain together with an added column 'area' set to the constant 'Basel'. Order by strain and return the first 10 rows.

The output should have this shape:

strain     | area
---------- | -----
sample-001 | Basel
sample-002 | Basel

Write a query and run it. The result is compared with the reference answer without considering row order.

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Explanation

Filter the table with like to keep divisions that match 'Basel.*'. Use map to add the constant area value, project the requested columns, order the rows by strain and keep the first 10.

like map

Reference answer

default
  .filter(division.like('Basel.*'))
  .map({area := 'Basel'})
  .project({strain, area})
  .orderBy({strain})
  .limit(10)