replaced '_concat_date_cols' and 'convert_to_unicode' from lib.pyx to parsing.pyx

Author: anmyachev

asv_bench/benchmarks/io/parsers.py

@@ -1,8 +1,7 @@
 import numpy as np
 
-from pandas._libs.tslibs.parsing import _does_string_look_like_datetime
-
-from pandas.io.parsers import _concat_date_cols
+from pandas._libs.tslibs.parsing import (
+    _concat_date_cols, _does_string_look_like_datetime)
 
 
 class DoesStringLookLikeDatetime(object):

pandas/_libs/lib.pyx

@@ -2311,117 +2311,3 @@ def fast_multiget(dict mapping, ndarray keys, default=np.nan):
             output[i] = default
 
     return maybe_convert_objects(output)
-
-
-@cython.wraparound(False)
-@cython.boundscheck(False)
-cdef inline object convert_to_unicode(object item,
-                                      bint keep_trivial_numbers):
-    """
-    Convert `item` to str.
-
-    Parameters
-    ----------
-    item : object
-    keep_trivial_numbers : bool
-        if True, then conversion (to string from integer/float zero)
-        is not performed
-
-    Returns
-    -------
-    str or int or float
-    """
-    cdef:
-        float64_t float_item
-
-    if keep_trivial_numbers:
-        if isinstance(item, int):
-            if <int>item == 0:
-                return item
-        elif isinstance(item, float):
-            float_item = item
-            if float_item == 0.0 or float_item != float_item:
-                return item
-
-    if not isinstance(item, str):
-        item = PyObject_Str(item)
-
-    return item
-
-
-@cython.wraparound(False)
-@cython.boundscheck(False)
-def _concat_date_cols(tuple date_cols, bint keep_trivial_numbers=True):
-    """
-    Concatenates elements from numpy arrays in `date_cols` into strings.
-
-    Parameters
-    ----------
-    date_cols : tuple of numpy arrays
-    keep_trivial_numbers : bool, default True
-        if True and len(date_cols) == 1, then
-        conversion (to string from integer/float zero) is not performed
-
-    Returns
-    -------
-    arr_of_rows : ndarray (dtype=object)
-
-    Examples
-    --------
-    >>> dates=np.array(['3/31/2019', '4/31/2019'], dtype=object)
-    >>> times=np.array(['11:20', '10:45'], dtype=object)
-    >>> result = _concat_date_cols((dates, times))
-    >>> result
-    array(['3/31/2019 11:20', '4/31/2019 10:45'], dtype=object)
-    """
-    cdef:
-        Py_ssize_t rows_count = 0, col_count = len(date_cols)
-        Py_ssize_t col_idx, row_idx
-        list list_to_join
-        cnp.ndarray[object] iters
-        object[::1] iters_view
-        flatiter it
-        cnp.ndarray[object] result
-        object[:] result_view
-
-    if col_count == 0:
-        return np.zeros(0, dtype=object)
-
-    if not all(util.is_array(array) for array in date_cols):
-        raise ValueError("not all elements from date_cols are numpy arrays")
-
-    rows_count = min(len(array) for array in date_cols)
-    result = np.zeros(rows_count, dtype=object)
-    result_view = result
-
-    if col_count == 1:
-        array = date_cols[0]
-        it = <flatiter>PyArray_IterNew(array)
-        for row_idx in range(rows_count):
-            item = PyArray_GETITEM(array, PyArray_ITER_DATA(it))
-            result_view[row_idx] = convert_to_unicode(item,
-                                                      keep_trivial_numbers)
-            PyArray_ITER_NEXT(it)
-    else:
-        # create fixed size list - more effecient memory allocation
-        list_to_join = [None] * col_count
-        iters = np.zeros(col_count, dtype=object)
-
-        # create memoryview of iters ndarray, that will contain some
-        # flatiter's for each array in `date_cols` - more effecient indexing
-        iters_view = iters
-        for col_idx, array in enumerate(date_cols):
-            iters_view[col_idx] = PyArray_IterNew(array)
-
-        # array elements that are on the same line are converted to one string
-        for row_idx in range(rows_count):
-            for col_idx, array in enumerate(date_cols):
-                # this cast is needed, because we did not find a way
-                # to efficiently store `flatiter` type objects in ndarray
-                it = <flatiter>iters_view[col_idx]
-                item = PyArray_GETITEM(array, PyArray_ITER_DATA(it))
-                list_to_join[col_idx] = convert_to_unicode(item, False)
-                PyArray_ITER_NEXT(it)
-            result_view[row_idx] = PyUnicode_Join(' ', list_to_join)
-
-    return result

pandas/_libs/tslibs/parsing.pyx

@@ -7,11 +7,19 @@ from io import StringIO
 
 from libc.string cimport strchr
 
+import cython
+
+from cpython cimport PyObject_Str, PyUnicode_Join
+
 from cpython.datetime cimport datetime, datetime_new, import_datetime
 from cpython.version cimport PY_VERSION_HEX
 import_datetime()
 
 import numpy as np
+cimport numpy as cnp
+from numpy cimport (PyArray_GETITEM, PyArray_ITER_DATA, PyArray_ITER_NEXT,
+                    PyArray_IterNew, flatiter, float64_t)
+cnp.import_array()
 
 # dateutil compat
 from dateutil.tz import (tzoffset,
@@ -26,7 +34,7 @@ from pandas._config import get_option
 
 from pandas._libs.tslibs.ccalendar import MONTH_NUMBERS
 from pandas._libs.tslibs.nattype import nat_strings, NaT
-from pandas._libs.tslibs.util cimport get_c_string_buf_and_size
+from pandas._libs.tslibs.util cimport is_array, get_c_string_buf_and_size
 
 cdef extern from "../src/headers/portable.h":
     int getdigit_ascii(char c, int default) nogil
@@ -880,3 +888,117 @@ def _guess_datetime_format(dt_str, dayfirst=False, dt_str_parse=du_parse,
         return guessed_format
     else:
         return None
+
+
+@cython.wraparound(False)
+@cython.boundscheck(False)
+cdef inline object convert_to_unicode(object item,
+                                      bint keep_trivial_numbers):
+    """
+    Convert `item` to str.
+
+    Parameters
+    ----------
+    item : object
+    keep_trivial_numbers : bool
+        if True, then conversion (to string from integer/float zero)
+        is not performed
+
+    Returns
+    -------
+    str or int or float
+    """
+    cdef:
+        float64_t float_item
+
+    if keep_trivial_numbers:
+        if isinstance(item, int):
+            if <int>item == 0:
+                return item
+        elif isinstance(item, float):
+            float_item = item
+            if float_item == 0.0 or float_item != float_item:
+                return item
+
+    if not isinstance(item, str):
+        item = PyObject_Str(item)
+
+    return item
+
+
+@cython.wraparound(False)
+@cython.boundscheck(False)
+def _concat_date_cols(tuple date_cols, bint keep_trivial_numbers=True):
+    """
+    Concatenates elements from numpy arrays in `date_cols` into strings.
+
+    Parameters
+    ----------
+    date_cols : tuple of numpy arrays
+    keep_trivial_numbers : bool, default True
+        if True and len(date_cols) == 1, then
+        conversion (to string from integer/float zero) is not performed
+
+    Returns
+    -------
+    arr_of_rows : ndarray (dtype=object)
+
+    Examples
+    --------
+    >>> dates=np.array(['3/31/2019', '4/31/2019'], dtype=object)
+    >>> times=np.array(['11:20', '10:45'], dtype=object)
+    >>> result = _concat_date_cols((dates, times))
+    >>> result
+    array(['3/31/2019 11:20', '4/31/2019 10:45'], dtype=object)
+    """
+    cdef:
+        Py_ssize_t rows_count = 0, col_count = len(date_cols)
+        Py_ssize_t col_idx, row_idx
+        list list_to_join
+        cnp.ndarray[object] iters
+        object[::1] iters_view
+        flatiter it
+        cnp.ndarray[object] result
+        object[:] result_view
+
+    if col_count == 0:
+        return np.zeros(0, dtype=object)
+
+    if not all(is_array(array) for array in date_cols):
+        raise ValueError("not all elements from date_cols are numpy arrays")
+
+    rows_count = min(len(array) for array in date_cols)
+    result = np.zeros(rows_count, dtype=object)
+    result_view = result
+
+    if col_count == 1:
+        array = date_cols[0]
+        it = <flatiter>PyArray_IterNew(array)
+        for row_idx in range(rows_count):
+            item = PyArray_GETITEM(array, PyArray_ITER_DATA(it))
+            result_view[row_idx] = convert_to_unicode(item,
+                                                      keep_trivial_numbers)
+            PyArray_ITER_NEXT(it)
+    else:
+        # create fixed size list - more effecient memory allocation
+        list_to_join = [None] * col_count
+        iters = np.zeros(col_count, dtype=object)
+
+        # create memoryview of iters ndarray, that will contain some
+        # flatiter's for each array in `date_cols` - more effecient indexing
+        iters_view = iters
+        for col_idx, array in enumerate(date_cols):
+            iters_view[col_idx] = PyArray_IterNew(array)
+
+        # array elements that are on the same line are converted to one string
+        for row_idx in range(rows_count):
+            for col_idx, array in enumerate(date_cols):
+                # this cast is needed, because we did not find a way
+                # to efficiently store `flatiter` type objects in ndarray
+                it = <flatiter>iters_view[col_idx]
+                item = PyArray_GETITEM(array, PyArray_ITER_DATA(it))
+                list_to_join[col_idx] = convert_to_unicode(item, False)
+                PyArray_ITER_NEXT(it)
+            result_view[row_idx] = PyUnicode_Join(' ', list_to_join)
+
+    return result

pandas/io/parsers.py

@@ -14,7 +14,6 @@
 import numpy as np
 
 import pandas._libs.lib as lib
-from pandas._libs.lib import _concat_date_cols
 import pandas._libs.ops as libops
 import pandas._libs.parsers as parsers
 from pandas._libs.tslibs import parsing
@@ -3187,7 +3186,7 @@ def _make_date_converter(date_parser=None, dayfirst=False,
                          infer_datetime_format=False, cache_dates=True):
     def converter(*date_cols):
         if date_parser is None:
-            strs = _concat_date_cols(date_cols)
+            strs = parsing._concat_date_cols(date_cols)
 
             try:
                 return tools.to_datetime(
@@ -3217,10 +3216,10 @@ def converter(*date_cols):
             except Exception:
                 try:
                     return tools.to_datetime(
-                        parsing.try_parse_dates(_concat_date_cols(date_cols),
-                                                parser=date_parser,
-                                                dayfirst=dayfirst),
-                        cache=cache_dates,
+                        parsing.try_parse_dates(
+                            parsing._concat_date_cols(date_cols),
+                            parser=date_parser,
+                            dayfirst=dayfirst),
                         errors='ignore')
                 except Exception:
                     return generic_parser(date_parser, *date_cols)

pandas/tests/io/parser/test_parse_dates.py

@@ -76,7 +76,7 @@ def date_parser(*date_cols):
         -------
         parsed : Series
         """
-        return parsing.try_parse_dates(parsers._concat_date_cols(date_cols))
+        return parsing.try_parse_dates(parsing._concat_date_cols(date_cols))
 
     result = parser.read_csv(StringIO(data), header=None,
                              date_parser=date_parser, prefix="X",