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Asked: 2026-05-22T22:55:08+00:00

I am looking at some Web2py code. The variable tokens is some kind of

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I am looking at some Web2py code.

The variable tokens is some kind of a list of strings. To be more precise, it is defined as tokens = form.vars.name.split() where form.vars.name is a string.

My question deals with the following instruction :

query = reduce(lambda a,b:a&b,[User.first_name.contains(k)|User.last_name.contains(k) for k in tokens])

Here are my questions :

  1. I know lambda a,b:a&b defines a function of a and b. What is a&b ?

  2. Is the contains method of User.first_name specific to Web2py ? Or does it exist in standard Python ?

  3. What is this | operator in User.first_name.contains(k)|User.last_name.contains(k) ?

  4. What does the reduce function do ?

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1 Answer

  1. Editorial Team
    1. In Web2Py & and | are not bitwise and/or here, but are used to build a special object that represents a database query! They correspond to AND and OR in SQL statements
    2. contains is part of Web2Pys DAL
    3. See 1.
    4. reduce is fold, a very fundamental higher order function that essentially reduces a list to a result, using the function given.
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