Replace imports of * with explicit imports

Remove compat_NaT which is never used after being defined

Remove other unused imports

Remove unused cdef enum NPY_TYPES

flake8 cleanup in period.pyx

Ref pandas-dev#17234

pandas/_libs/hashtable.pyx

@@ -2,7 +2,27 @@
 
 from cpython cimport PyObject, Py_INCREF, PyList_Check, PyTuple_Check
 
-from khash cimport *
+from khash cimport (
+    khiter_t,
+
+    kh_str_t, kh_init_str, kh_put_str, kh_exist_str,
+    kh_get_str, kh_destroy_str, kh_resize_str,
+
+    kh_put_strbox, kh_get_strbox, kh_init_strbox,
+
+    kh_int64_t, kh_init_int64, kh_resize_int64, kh_destroy_int64,
+    kh_get_int64, kh_exist_int64, kh_put_int64,
+
+    kh_float64_t, kh_exist_float64, kh_put_float64, kh_init_float64,
+    kh_get_float64, kh_destroy_float64, kh_resize_float64,
+
+    kh_resize_uint64, kh_exist_uint64, kh_destroy_uint64, kh_put_uint64,
+    kh_get_uint64, kh_init_uint64,
+
+    kh_destroy_pymap, kh_exist_pymap, kh_init_pymap, kh_get_pymap,
+    kh_put_pymap, kh_resize_pymap)
+
+
 from numpy cimport *
 
 from libc.stdlib cimport malloc, free

pandas/_libs/index.pyx

@@ -1,8 +1,6 @@
 # cython: profile=False
 
-from numpy cimport ndarray
-
-from numpy cimport (float64_t, int32_t, int64_t, uint8_t,
+from numpy cimport (ndarray, float64_t, int32_t, int64_t, uint8_t, uint64_t,
                     NPY_DATETIME, NPY_TIMEDELTA)
 cimport cython
 
@@ -16,7 +14,9 @@ cimport util
 import numpy as np
 
 cimport tslib
-from hashtable cimport *
+
+from hashtable cimport HashTable
+
 from pandas._libs import tslib, algos, hashtable as _hash
 from pandas._libs.tslib import Timestamp, Timedelta
 from datetime import datetime, timedelta

pandas/_libs/join_func_helper.pxi.in

@@ -9,6 +9,8 @@ WARNING: DO NOT edit .pxi FILE directly, .pxi is generated from .pxi.in
 # asof_join_by
 #----------------------------------------------------------------------
 
+from hashtable cimport PyObjectHashTable, UInt64HashTable, Int64HashTable
+
 {{py:
 
 # table_type, by_dtype
@@ -23,7 +25,6 @@ on_dtypes = ['uint8_t', 'uint16_t', 'uint32_t', 'uint64_t',
 }}
 
 
-from hashtable cimport *
 
 {{for table_type, by_dtype in by_dtypes}}
 {{for on_dtype in on_dtypes}}

pandas/_libs/lib.pyx

@@ -10,21 +10,14 @@ from numpy cimport *
 
 np.import_array()
 
-cdef extern from "numpy/arrayobject.h":
-    cdef enum NPY_TYPES:
-        NPY_intp "NPY_INTP"
-
 from libc.stdlib cimport malloc, free
 
-from cpython cimport (PyDict_New, PyDict_GetItem, PyDict_SetItem,
-                      PyDict_Contains, PyDict_Keys,
-                      Py_INCREF, PyTuple_SET_ITEM,
+from cpython cimport (Py_INCREF, PyTuple_SET_ITEM,
                       PyList_Check, PyFloat_Check,
                       PyString_Check,
                       PyBytes_Check,
-                      PyTuple_SetItem,
+                      PyUnicode_Check,
                       PyTuple_New,
-                      PyObject_SetAttrString,
                       PyObject_RichCompareBool,
                       PyBytes_GET_SIZE,
                       PyUnicode_GET_SIZE,
@@ -55,7 +48,18 @@ cdef double NAN = nan
 from datetime import datetime as pydatetime
 
 # this is our tseries.pxd
-from datetime cimport *
+from datetime cimport (
+    get_timedelta64_value, get_datetime64_value,
+    npy_timedelta, npy_datetime,
+    PyDateTime_Check, PyDate_Check, PyTime_Check, PyDelta_Check,
+    PyDateTime_GET_YEAR,
+    PyDateTime_GET_MONTH,
+    PyDateTime_GET_DAY,
+    PyDateTime_DATE_GET_HOUR,
+    PyDateTime_DATE_GET_MINUTE,
+    PyDateTime_DATE_GET_SECOND,
+    PyDateTime_IMPORT)
+
 
 from tslib cimport (convert_to_tsobject, convert_to_timedelta64,
                     _check_all_nulls)

pandas/_libs/parsers.pyx

@@ -32,7 +32,7 @@ cdef extern from "stdlib.h":
 cimport cython
 cimport numpy as cnp
 
-from numpy cimport ndarray, uint8_t, uint64_t
+from numpy cimport ndarray, uint8_t, uint64_t, int64_t
 
 import numpy as np
 cimport util
@@ -57,7 +57,14 @@ import os
 
 cnp.import_array()
 
-from khash cimport *
+from khash cimport (
+    khiter_t,
+    kh_str_t, kh_init_str, kh_put_str, kh_exist_str,
+    kh_get_str, kh_destroy_str,
+    kh_float64_t, kh_get_float64, kh_destroy_float64,
+    kh_put_float64, kh_init_float64,
+    kh_strbox_t, kh_put_strbox, kh_get_strbox, kh_init_strbox,
+    kh_destroy_strbox)
 
 import sys
 

pandas/_libs/period.pyx

@@ -2,6 +2,7 @@ from datetime import datetime, date, timedelta
 import operator
 
 from cpython cimport (
+    PyUnicode_Check,
     PyObject_RichCompareBool,
     Py_EQ, Py_NE,
 )
@@ -19,7 +20,16 @@ from pandas import compat
 from pandas.compat import PY2
 
 cimport cython
-from datetime cimport *
+
+from datetime cimport (
+    is_leapyear,
+    PyDateTime_IMPORT,
+    pandas_datetimestruct,
+    pandas_datetimestruct_to_datetime,
+    pandas_datetime_to_datetimestruct,
+    PANDAS_FR_ns,
+    INT32_MIN)
+
 cimport util, lib
 from lib cimport is_null_datetimelike, is_period
 from pandas._libs import tslib, lib
@@ -30,8 +40,7 @@ from tslib cimport (
     _is_utc,
     _is_tzlocal,
     _get_dst_info,
-    _nat_scalar_rules,
-)
+    _nat_scalar_rules)
 
 from pandas.tseries import offsets
 from pandas.core.tools.datetimes import parse_time_string

pandas/_libs/src/properties.pyx

@@ -1,4 +1,5 @@
-from cpython cimport PyDict_Contains, PyDict_GetItem, PyDict_GetItem
+from cpython cimport (
+    PyDict_Contains, PyDict_GetItem, PyDict_GetItem, PyDict_SetItem)
 
 
 cdef class cache_readonly(object):

pandas/_libs/src/skiplist.pyx

@@ -6,10 +6,6 @@
 
 # Cython version: Wes McKinney
 
-cdef extern from "numpy/arrayobject.h":
-
-    void import_array()
-
 cdef extern from "math.h":
     double log(double x)
 
@@ -25,7 +21,7 @@ import numpy as np
 from random import random
 
 # initialize numpy
-import_array()
+np.import_array()
 
 # TODO: optimize this, make less messy
 

pandas/_libs/tslib.pyx

@@ -4,8 +4,8 @@ import warnings
 
 cimport numpy as np
 from numpy cimport (int8_t, int32_t, int64_t, import_array, ndarray,
+                    float64_t,
                     NPY_INT64, NPY_DATETIME, NPY_TIMEDELTA)
-from datetime cimport get_datetime64_value, get_timedelta64_value
 import numpy as np
 
 import sys
@@ -30,20 +30,47 @@ cdef extern from "datetime_helper.h":
     double total_seconds(object)
 
 # this is our datetime.pxd
-from datetime cimport cmp_pandas_datetimestruct
 from libc.stdlib cimport free
 
 from util cimport (is_integer_object, is_float_object, is_datetime64_object,
                    is_timedelta64_object, INT64_MAX)
 cimport util
 
-from datetime cimport *
-from khash cimport *
-cimport cython
-
+# this is our datetime.pxd
+from datetime cimport (
+    pandas_datetimestruct,
+    pandas_datetime_to_datetimestruct,
+    pandas_datetimestruct_to_datetime,
+    cmp_pandas_datetimestruct,
+    days_per_month_table,
+    get_datetime64_value,
+    get_timedelta64_value,
+    get_datetime64_unit,
+    PANDAS_DATETIMEUNIT,
+    _string_to_dts,
+    _pydatetime_to_dts,
+    _date_to_datetime64,
+    npy_datetime,
+    is_leapyear,
+    dayofweek,
+    PANDAS_FR_ns,
+    PyDateTime_Check, PyDate_Check,
+    PyDateTime_IMPORT,
+    timedelta, datetime
+    )
+
+# stdlib datetime imports
 from datetime import timedelta, datetime
 from datetime import time as datetime_time
 
+from khash cimport (
+    khiter_t,
+    kh_destroy_int64, kh_put_int64,
+    kh_init_int64, kh_int64_t,
+    kh_resize_int64, kh_get_int64)
+
+cimport cython
+
 import re
 
 # dateutil compat
@@ -81,15 +108,6 @@ PyDateTime_IMPORT
 cdef int64_t NPY_NAT = util.get_nat()
 iNaT = NPY_NAT
 
-# < numpy 1.7 compat for NaT
-compat_NaT = np.array([NPY_NAT]).astype('m8[ns]').item()
-
-
-try:
-    basestring
-except NameError: # py3
-    basestring = str
-
 
 cdef inline object create_timestamp_from_ts(
         int64_t value, pandas_datetimestruct dts,
@@ -314,7 +332,7 @@ class Timestamp(_Timestamp):
         tz : string / timezone object, default None
             Timezone to localize to
         """
-        if isinstance(tz, basestring):
+        if isinstance(tz, string_types):
             tz = maybe_get_tz(tz)
         return cls(datetime.now(tz))
 
@@ -615,7 +633,7 @@ class Timestamp(_Timestamp):
         if self.tzinfo is None:
             # tz naive, localize
             tz = maybe_get_tz(tz)
-            if not isinstance(ambiguous, basestring):
+            if not isinstance(ambiguous, string_types):
                 ambiguous =   [ambiguous]
             value = tz_localize_to_utc(np.array([self.value], dtype='i8'), tz,
                                        ambiguous=ambiguous, errors=errors)[0]

pandas/_libs/window.pyx

@@ -56,7 +56,13 @@ cdef inline int int_min(int a, int b): return a if a <= b else b
 
 from util cimport numeric
 
-from skiplist cimport *
+from skiplist cimport (
+    skiplist_t,
+    skiplist_init,
+    skiplist_destroy,
+    skiplist_get,
+    skiplist_insert,
+    skiplist_remove)
 
 cdef extern from "../src/headers/math.h":
     double sqrt(double x) nogil