Configuration

Naming Styles

Pylint recognizes a number of different name types internally. With a few exceptions, the type of the name is governed by the location the assignment to a name is found in, and not the type of object assigned.

module
Module and package names, same as the file names.
const
Module-level constants, any variable defined at module level that is not bound to a class object.
class
Names in class statements, as well as names bound to class objects at module level.
function
Functions, toplevel or nested in functions or methods.
method
Methods, functions defined in class bodies. Includes static and class methods.
attr
Attributes created on class instances inside methods.
argument
Arguments to any function type, including lambdas.
variable
Local variables in function scopes.
class-attribute
Attributes defined in class bodies.
inlinevar
Loop variables in list comprehensions and generator expressions.

For each naming style, a separate regular expression matching valid names of this type can be defined. By default, the regular expressions will enforce PEP8 names.

Regular expressions for the names are anchored at the beginning, any anchor for the end must be supplied explicitly. Any name not matching the regular expression will lead to an instance of invalid-name.

--module-rgx=<regex>

Default value: (([a-z_][a-z0-9_]*)|([A-Z][a-zA-Z0-9]+))$

--const-rgx=<regex>

Default value: (([A-Z_][A-Z0-9_]*)|(__.*__))$

--class-rgx=<regex>

Default value: [A-Z_][a-zA-Z0-9]+$

--function-rgx=<regex>

Default value: [a-z_][a-z0-9_]{2,30}$

--method-rgx=<regex>

Default value: [a-z_][a-z0-9_]{2,30}$

--attr-rgx=<regex>

Default value: [a-z_][a-z0-9_]{2,30}$

--argument-rgx=<regex>

Default value: [a-z_][a-z0-9_]{2,30}$

--variable-rgx=<regex>

Default value: [a-z_][a-z0-9_]{2,30}$

--class-attribute-rgx=<regex>

Default value: ([A-Za-z_][A-Za-z0-9_]{2,30}|(__.*__))$

--inlinevar-rgx=<regex>

Default value: [A-Za-z_][A-Za-z0-9_]*$

Multiple Naming Styles

Large code bases that have been worked on for multiple years often exhibit an evolution in style as well. In some cases, modules can be in the same package, but still have different naming style based on the stratum they belong to. However, intra-module consistency should still be required, to make changes inside a single file easier. For this case, Pylint supports regular expression with several named capturing group.

Rather than emitting name warnings immediately, Pylint will determine the prevalent naming style inside each module and enforce it on all names.

Consider the following (simplified) example:

pylint --function-rgx='(?:(?P<snake>[a-z_]+)|(?P<camel>_?[A-Z]+))$' sample.py

The regular expression defines two naming styles, snake for snake-case names, and camel for camel-case names.

In sample.py, the function name on line 1 and 7 will mark the module and enforce the match of named group snake for the remaining names in the module:

def valid_snake_case(arg):
   ...

def InvalidCamelCase(arg):
   ...

def more_valid_snake_case(arg):
 ...

Because of this, the name on line 4 will trigger an invalid-name warning, even though the name matches the given regex.

Matches named exempt or ignore can be used for non-tainting names, to prevent built-in or interface-dictated names to trigger certain naming styles.

--name-group=<name1:name2:...,...>

Default value: empty

Format: comma-separated groups of colon-separated names.

This option can be used to combine name styles. For example, function:method enforces that functions and methods use the same style, and a style triggered by either name type carries over to the other. This requires that the regular expression for the combined name types use the same group names.

Name Hints

--include-naming-hint=y|n

Default: off

Include a hint for the correct name format with every invalid-name warning.

Name hints default to the regular expression, but can be separately configured with the --<name-type>-hint options.