TYP: Typing hints in pandas/io/formats/{css,csvs}.py

Author: MomIsBestFriend

pandas/io/formats/css.py

@@ -1,24 +1,39 @@
-"""Utilities for interpreting CSS from Stylers for formatting non-HTML outputs
+"""
+Utilities for interpreting CSS from Stylers for formatting non-HTML outputs.
 """
 
 import re
 import warnings
 
 
 class CSSWarning(UserWarning):
-    """This CSS syntax cannot currently be parsed"""
+    """
+    This CSS syntax cannot currently be parsed.
+    """
 
     pass
 
 
 def _side_expander(prop_fmt: str):
-    def expand(self, prop, value):
+    """
+    Parameters
+    ----------
+    prop_fmt : str
+    """
+
+    def expand(self, prop, value: str):
+        """
+        Parameters
+        ----------
+        prop
+        value : str
+        """
         tokens = value.split()
         try:
             mapping = self.SIDE_SHORTHANDS[len(tokens)]
         except KeyError:
             warnings.warn(
-                f'Could not expand "{prop}: {value}"', CSSWarning,
+                f"Could not expand {prop}: {value}", CSSWarning,
             )
             return
         for key, idx in zip(self.SIDES, mapping):
@@ -28,12 +43,13 @@ def expand(self, prop, value):
 
 
 class CSSResolver:
-    """A callable for parsing and resolving CSS to atomic properties
-
+    """
+    A callable for parsing and resolving CSS to atomic properties.
     """
 
     def __call__(self, declarations_str, inherited=None):
-        """ the given declarations to atomic properties
+        """
+        The given declarations to atomic properties.
 
         Parameters
         ----------
@@ -46,8 +62,8 @@ def __call__(self, declarations_str, inherited=None):
 
         Returns
         -------
-        props : dict
-            Atomic CSS 2.2 properties
+        dict
+            Atomic CSS 2.2 properties.
 
         Examples
         --------
@@ -69,7 +85,6 @@ def __call__(self, declarations_str, inherited=None):
          ('font-size', '24pt'),
          ('font-weight', 'bold')]
         """
-
         props = dict(self.atomize(self.parse(declarations_str)))
         if inherited is None:
             inherited = {}
@@ -172,7 +187,9 @@ def __call__(self, declarations_str, inherited=None):
 
     def size_to_pt(self, in_val, em_pt=None, conversions=UNIT_RATIOS):
         def _error():
-            warnings.warn(f"Unhandled size: {repr(in_val)}", CSSWarning)
+            warnings.warn(
+                f"Unhandled size: {repr(in_val)}", CSSWarning,
+            )
             return self.size_to_pt("1!!default", conversions=conversions)
 
         try:
@@ -235,10 +252,15 @@ def atomize(self, declarations):
     expand_margin = _side_expander("margin-{:s}")
     expand_padding = _side_expander("padding-{:s}")
 
-    def parse(self, declarations_str):
-        """Generates (prop, value) pairs from declarations
+    def parse(self, declarations_str: str):
+        """
+        Generates (prop, value) pairs from declarations.
 
         In a future version may generate parsed tokens from tinycss/tinycss2
+
+        Parameters
+        ----------
+        declarations_str : str
         """
         for decl in declarations_str.split(";"):
             if not decl.strip():

pandas/io/formats/csvs.py

@@ -5,7 +5,7 @@
 import csv as csvlib
 from io import StringIO
 import os
-from typing import List
+from typing import List, Optional, Sequence, Union
 import warnings
 from zipfile import ZipFile
 
@@ -21,6 +21,8 @@
 )
 from pandas.core.dtypes.missing import notna
 
+from pandas._typing import FilePathOrBuffer
+
 from pandas.io.common import (
     get_compression_method,
     get_filepath_or_buffer,
@@ -33,27 +35,26 @@ class CSVFormatter:
     def __init__(
         self,
         obj,
-        path_or_buf=None,
-        sep=",",
-        na_rep="",
+        path_or_buf: Optional[FilePathOrBuffer[str]] = None,
+        sep: str = ",",
+        na_rep: str = "",
         float_format=None,
         cols=None,
-        header=True,
-        index=True,
+        header: Union[bool, Sequence[str]] = True,
+        index: bool = True,
         index_label=None,
-        mode="w",
-        encoding=None,
+        mode: str = "w",
+        encoding: Optional[str] = None,
         compression="infer",
-        quoting=None,
-        line_terminator="\n",
-        chunksize=None,
-        quotechar='"',
-        date_format=None,
-        doublequote=True,
+        quoting: Optional[int] = None,
+        line_terminator: Optional[str] = "\n",
+        chunksize: Optional[int] = None,
+        quotechar: Optional[str] = '"',
+        date_format: Optional[str] = None,
+        doublequote: bool = True,
         escapechar=None,
-        decimal=".",
+        decimal: Optional[str] = ".",
     ):
-
         self.obj = obj
 
         if path_or_buf is None:
@@ -154,14 +155,17 @@ def __init__(
         if not index:
             self.nlevels = 0
 
-    def save(self):
+    def save(self) -> None:
         """
-        Create the writer & save
+        Create the writer & save.
         """
         # GH21227 internal compression is not used when file-like passed.
         if self.compression and hasattr(self.path_or_buf, "write"):
-            msg = "compression has no effect when passing file-like object as input."
-            warnings.warn(msg, RuntimeWarning, stacklevel=2)
+            warnings.warn(
+                "compression has no effect when passing file-like object as input.",
+                RuntimeWarning,
+                stacklevel=2,
+            )
 
         # when zip compression is called.
         is_zip = isinstance(self.path_or_buf, ZipFile) or (
@@ -223,7 +227,6 @@ def save(self):
                     _fh.close()
 
     def _save_header(self):
-
         writer = self.writer
         obj = self.obj
         index_label = self.index_label
@@ -306,8 +309,7 @@ def _save_header(self):
                 encoded_labels.extend([""] * len(columns))
                 writer.writerow(encoded_labels)
 
-    def _save(self):
-
+    def _save(self) -> None:
         self._save_header()
 
         nrows = len(self.data_index)
@@ -324,8 +326,7 @@ def _save(self):
 
             self._save_chunk(start_i, end_i)
 
-    def _save_chunk(self, start_i: int, end_i: int):
-
+    def _save_chunk(self, start_i: int, end_i: int) -> None:
         data_index = self.data_index
 
         # create the data for a chunk