From 66625fbc98841168999bf808f2ecd33c36bfaa61 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Sun, 31 Oct 2021 16:49:47 -0700
Subject: [PATCH] CLN: tighten flake8/cython.cfg

---
 flake8/cython.cfg               |  4 ----
 pandas/_libs/algos.pyx          | 10 +++++-----
 pandas/_libs/hashing.pyx        |  5 ++---
 pandas/_libs/internals.pyx      |  8 ++++----
 pandas/_libs/tslibs/parsing.pyx | 12 ++++++------
 pandas/_libs/tslibs/period.pyx  | 10 +++++-----
 pandas/_libs/writers.pyx        | 16 ++++++++--------
 7 files changed, 30 insertions(+), 35 deletions(-)

diff --git a/flake8/cython.cfg b/flake8/cython.cfg
index a9584ad2e0994..bf1f41647b34e 100644
--- a/flake8/cython.cfg
+++ b/flake8/cython.cfg
@@ -9,9 +9,5 @@ extend_ignore=
     E226,
     # missing whitespace around bitwise or shift operator
     E227,
-    # ambiguous variable name (# FIXME maybe this one can be fixed)
-    E741,
     # invalid syntax
     E999,
-    # invalid escape sequence (# FIXME maybe this one can be fixed)
-    W605,
diff --git a/pandas/_libs/algos.pyx b/pandas/_libs/algos.pyx
index 68c09f83e1cdf..3d099a53163bc 100644
--- a/pandas/_libs/algos.pyx
+++ b/pandas/_libs/algos.pyx
@@ -259,15 +259,15 @@ cdef inline numeric_t kth_smallest_c(numeric_t* arr, Py_ssize_t k, Py_ssize_t n)
     in groupby.pyx
     """
     cdef:
-        Py_ssize_t i, j, l, m
+        Py_ssize_t i, j, left, m
         numeric_t x
 
-    l = 0
+    left = 0
     m = n - 1
 
-    while l < m:
+    while left < m:
         x = arr[k]
-        i = l
+        i = left
         j = m
 
         while 1:
@@ -284,7 +284,7 @@ cdef inline numeric_t kth_smallest_c(numeric_t* arr, Py_ssize_t k, Py_ssize_t n)
                 break
 
         if j < k:
-            l = i
+            left = i
         if k < i:
             m = j
     return arr[k]
diff --git a/pandas/_libs/hashing.pyx b/pandas/_libs/hashing.pyx
index 75eee4d432637..39caf04ddf2f8 100644
--- a/pandas/_libs/hashing.pyx
+++ b/pandas/_libs/hashing.pyx
@@ -52,7 +52,7 @@ def hash_object_array(
     mixed array types will raise TypeError.
     """
     cdef:
-        Py_ssize_t i, l, n
+        Py_ssize_t i, n
         uint64_t[:] result
         bytes data, k
         uint8_t *kb
@@ -97,8 +97,7 @@ def hash_object_array(
                 "must be string or null"
             )
 
-        l = len(data)
-        lens[i] = l
+        lens[i] = len(data)
         cdata = data
 
         # keep the references alive through the end of the
diff --git a/pandas/_libs/internals.pyx b/pandas/_libs/internals.pyx
index 957432df20395..ac423ef6c0ca2 100644
--- a/pandas/_libs/internals.pyx
+++ b/pandas/_libs/internals.pyx
@@ -179,7 +179,7 @@ cdef class BlockPlacement:
     cdef BlockPlacement iadd(self, other):
         cdef:
             slice s = self._ensure_has_slice()
-            Py_ssize_t other_int, start, stop, step, l
+            Py_ssize_t other_int, start, stop, step
 
         if is_integer_object(other) and s is not None:
             other_int = <Py_ssize_t>other
@@ -188,7 +188,7 @@ cdef class BlockPlacement:
                 # BlockPlacement is treated as immutable
                 return self
 
-            start, stop, step, l = slice_get_indices_ex(s)
+            start, stop, step, _ = slice_get_indices_ex(s)
             start += other_int
             stop += other_int
 
@@ -226,14 +226,14 @@ cdef class BlockPlacement:
         """
         cdef:
             slice nv, s = self._ensure_has_slice()
-            Py_ssize_t other_int, start, stop, step, l
+            Py_ssize_t other_int, start, stop, step
             ndarray[intp_t, ndim=1] newarr
 
         if s is not None:
             # see if we are either all-above or all-below, each of which
             #  have fastpaths available.
 
-            start, stop, step, l = slice_get_indices_ex(s)
+            start, stop, step, _ = slice_get_indices_ex(s)
 
             if start < loc and stop <= loc:
                 # We are entirely below, nothing to increment
diff --git a/pandas/_libs/tslibs/parsing.pyx b/pandas/_libs/tslibs/parsing.pyx
index b8f957a4c2ea8..f2b480642e083 100644
--- a/pandas/_libs/tslibs/parsing.pyx
+++ b/pandas/_libs/tslibs/parsing.pyx
@@ -808,12 +808,12 @@ class _timelex:
         # TODO: Change \s --> \s+ (this doesn't match existing behavior)
         # TODO: change the punctuation block to punc+ (does not match existing)
         # TODO: can we merge the two digit patterns?
-        tokens = re.findall('\s|'
-                            '(?<![\.\d])\d+\.\d+(?![\.\d])'
-                            '|\d+'
-                            '|[a-zA-Z]+'
-                            '|[\./:]+'
-                            '|[^\da-zA-Z\./:\s]+', stream)
+        tokens = re.findall(r"\s|"
+                            r"(?<![\.\d])\d+\.\d+(?![\.\d])"
+                            r"|\d+"
+                            r"|[a-zA-Z]+"
+                            r"|[\./:]+"
+                            r"|[^\da-zA-Z\./:\s]+", stream)
 
         # Re-combine token tuples of the form ["59", ",", "456"] because
         # in this context the "," is treated as a decimal
diff --git a/pandas/_libs/tslibs/period.pyx b/pandas/_libs/tslibs/period.pyx
index dcf4323bc8755..337876d610c5e 100644
--- a/pandas/_libs/tslibs/period.pyx
+++ b/pandas/_libs/tslibs/period.pyx
@@ -983,14 +983,14 @@ def periodarr_to_dt64arr(const int64_t[:] periodarr, int freq):
     """
     cdef:
         int64_t[:] out
-        Py_ssize_t i, l
+        Py_ssize_t i, N
 
     if freq < 6000:  # i.e. FR_DAY, hard-code to avoid need to cast
-        l = len(periodarr)
-        out = np.empty(l, dtype="i8")
+        N = len(periodarr)
+        out = np.empty(N, dtype="i8")
 
         # We get here with freqs that do not correspond to a datetime64 unit
-        for i in range(l):
+        for i in range(N):
             out[i] = period_ordinal_to_dt64(periodarr[i], freq)
 
         return out.base  # .base to access underlying np.ndarray
@@ -2248,7 +2248,7 @@ cdef class _Period(PeriodMixin):
         return (Period, object_state)
 
     def strftime(self, fmt: str) -> str:
-        """
+        r"""
         Returns the string representation of the :class:`Period`, depending
         on the selected ``fmt``. ``fmt`` must be a string
         containing one or several directives.  The method recognizes the same
diff --git a/pandas/_libs/writers.pyx b/pandas/_libs/writers.pyx
index 79f551c9ebf6f..46f04cf8e15b3 100644
--- a/pandas/_libs/writers.pyx
+++ b/pandas/_libs/writers.pyx
@@ -125,15 +125,15 @@ def max_len_string_array(pandas_string[:] arr) -> Py_ssize_t:
     Return the maximum size of elements in a 1-dim string array.
     """
     cdef:
-        Py_ssize_t i, m = 0, l = 0, length = arr.shape[0]
+        Py_ssize_t i, m = 0, wlen = 0, length = arr.shape[0]
         pandas_string val
 
     for i in range(length):
         val = arr[i]
-        l = word_len(val)
+        wlen = word_len(val)
 
-        if l > m:
-            m = l
+        if wlen > m:
+            m = wlen
 
     return m
 
@@ -143,14 +143,14 @@ cpdef inline Py_ssize_t word_len(object val):
     Return the maximum length of a string or bytes value.
     """
     cdef:
-        Py_ssize_t l = 0
+        Py_ssize_t wlen = 0
 
     if isinstance(val, str):
-        l = PyUnicode_GET_LENGTH(val)
+        wlen = PyUnicode_GET_LENGTH(val)
     elif isinstance(val, bytes):
-        l = PyBytes_GET_SIZE(val)
+        wlen = PyBytes_GET_SIZE(val)
 
-    return l
+    return wlen
 
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