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map()

Creates a map node with optional configuration to the pipeline. This node calls the specified function to create a list matching the output schema from the one matching the input schema.

map(input_schema, output_schema, fn, config=None)

Parameters​

  • input_schema - str or tuple[str]

    • A column name or all column names of the input list

    • Each column name in the schema should be a string, containing alphanumerical characters and underscores.

  • output_schema - str or tuple[str]

    • A column name or all column names of the output list

    • Each column name in the schema should be a string, containing alphanumerical characters and underscores.

  • fn - Operator, lambda, or callable

    • A function that is used to map an item in the input list to an item in the output list.

    • It can be an operator from Towhee Hub, a lambda, or a callable function.

  • config - dict or None

    • Optional configuration for the current node.

    • It defaults to None and can be a dictionary containing the configuration items. See AutoConfig API for details.

Returns​

A not-callable Pipeline object with this map node appended

Example​

from towhee import pipe, ops

# run with lambda
p = pipe.input('a').map('a', 'b', lambda x: x+1).output('b')
p(1).get() # return [2]

# run with callable
def func(x):
    return x+1
p = pipe.input('a').map('a', 'b', func).output('b')
p(1).get() # return [2]

# run with the operator in hub
p = (pipe.input('path')
         .map('path', 'img', ops.towhee.image_decode())
         .output('img'))
p('https://github.com/towhee-io/towhee/raw/main/towhee_logo.png')