PYL-W0108 · Unnecessary lambda expression

Unnecessary lambda expression PYL-W0108

Anti-pattern

Major

8 days ago — 4 years old

Lambda may not be necessary

packages/jet_bridge_base/jet_bridge_base/filters/filter.py

157        lookups.ENDS_WITH: {'operator': False, 'func': safe_endswith, 'pre_process': lambda x: safe_not_array(x)},
158        lookups.IS_NULL: {'operator': False, 'func': is_null, 'field_class': BooleanField, 'pre_process': lambda x: safe_not_array(x)},
159        lookups.IS_EMPTY: {'operator': False, 'func': is_empty, 'field_class': BooleanField, 'pre_process': lambda x: safe_not_array(x)},
160        lookups.JSON_ICONTAINS: {'operator': False, 'func': json_icontains, 'field_class': CharField, 'pre_process': lambda x: safe_not_array(x)},161        lookups.COVEREDBY: {'operator': False, 'func': coveredby, 'pre_process': lambda x: safe_not_array(x)}
162    }
163

Lambda may not be necessary

packages/jet_bridge_base/jet_bridge_base/filters/filter.py

152        lookups.LT: {'operator': '__lt__', 'pre_process': lambda x: safe_not_array(x)},
153        lookups.LTE: {'operator': '__le__', 'pre_process': lambda x: safe_not_array(x)},
154        lookups.ICONTAINS: {'operator': False, 'func': safe_icontains, 'pre_process': lambda x: safe_not_array(x)},
155        lookups.IN: {'operator': False, 'func': safe_in, 'field_kwargs': {'many': True}, 'pre_process': lambda x: safe_array(x)},156        lookups.STARTS_WITH: {'operator': False, 'func': safe_startswith, 'pre_process': lambda x: safe_not_array(x)},
157        lookups.ENDS_WITH: {'operator': False, 'func': safe_endswith, 'pre_process': lambda x: safe_not_array(x)},
158        lookups.IS_NULL: {'operator': False, 'func': is_null, 'field_class': BooleanField, 'pre_process': lambda x: safe_not_array(x)},

Lambda may not be necessary

packages/jet_bridge_base/jet_bridge_base/filters/filter.py

158        lookups.IS_NULL: {'operator': False, 'func': is_null, 'field_class': BooleanField, 'pre_process': lambda x: safe_not_array(x)},
159        lookups.IS_EMPTY: {'operator': False, 'func': is_empty, 'field_class': BooleanField, 'pre_process': lambda x: safe_not_array(x)},
160        lookups.JSON_ICONTAINS: {'operator': False, 'func': json_icontains, 'field_class': CharField, 'pre_process': lambda x: safe_not_array(x)},
161        lookups.COVEREDBY: {'operator': False, 'func': coveredby, 'pre_process': lambda x: safe_not_array(x)}162    }
163
164    def __init__(self, name=None, column=None, lookup=lookups.DEFAULT_LOOKUP, exclude=False):

Lambda may not be necessary

packages/jet_bridge_base/jet_bridge_base/filters/filter.py

156        lookups.STARTS_WITH: {'operator': False, 'func': safe_startswith, 'pre_process': lambda x: safe_not_array(x)},
157        lookups.ENDS_WITH: {'operator': False, 'func': safe_endswith, 'pre_process': lambda x: safe_not_array(x)},
158        lookups.IS_NULL: {'operator': False, 'func': is_null, 'field_class': BooleanField, 'pre_process': lambda x: safe_not_array(x)},
159        lookups.IS_EMPTY: {'operator': False, 'func': is_empty, 'field_class': BooleanField, 'pre_process': lambda x: safe_not_array(x)},160        lookups.JSON_ICONTAINS: {'operator': False, 'func': json_icontains, 'field_class': CharField, 'pre_process': lambda x: safe_not_array(x)},
161        lookups.COVEREDBY: {'operator': False, 'func': coveredby, 'pre_process': lambda x: safe_not_array(x)}
162    }

Lambda may not be necessary

packages/jet_bridge_base/jet_bridge_base/filters/filter.py

155        lookups.IN: {'operator': False, 'func': safe_in, 'field_kwargs': {'many': True}, 'pre_process': lambda x: safe_array(x)},
156        lookups.STARTS_WITH: {'operator': False, 'func': safe_startswith, 'pre_process': lambda x: safe_not_array(x)},
157        lookups.ENDS_WITH: {'operator': False, 'func': safe_endswith, 'pre_process': lambda x: safe_not_array(x)},
158        lookups.IS_NULL: {'operator': False, 'func': is_null, 'field_class': BooleanField, 'pre_process': lambda x: safe_not_array(x)},159        lookups.IS_EMPTY: {'operator': False, 'func': is_empty, 'field_class': BooleanField, 'pre_process': lambda x: safe_not_array(x)},
160        lookups.JSON_ICONTAINS: {'operator': False, 'func': json_icontains, 'field_class': CharField, 'pre_process': lambda x: safe_not_array(x)},
161        lookups.COVEREDBY: {'operator': False, 'func': coveredby, 'pre_process': lambda x: safe_not_array(x)}

Description

A lambda that calls a function without modifying any of its parameters is unnecessary. Python functions are first-class objects and can be passed around in the same way as the resulting lambda. It is recommended to remove the lambda and use the function directly.

It is preferred to use the function hash directly as the lambda function calls the same function without any modifications. Another reason to avoid the lambda function here is that it makes debugging difficult. Lambdas show as <lambda> in tracebacks, where functions will display the function’s name.

Bad practice

items = [1, 2, 3]

hashify = lambda x: hash(x)
hashed_items = map(hashify, items)

jet-admin / jet-bridge

Bad practice

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