Added get. Also added cytoolz.cpython for additional C bindings.

cytoolz/__init__.pxd

@@ -1,6 +1,6 @@
 from .itertoolz cimport (groupby, frequencies, reduceby,
                          first, second, nth, take, drop, rest, last,
-                         concat, concatv, isdistinct, interpose, unique,
+                         get, concat, concatv, isdistinct, interpose, unique,
                          isiterable, remove, iterate, accumulate,
                          count, cons, take_nth)
 

cytoolz/__init__.py

@@ -1,6 +1,6 @@
 from .itertoolz import (groupby, frequencies, reduceby,
                         first, second, nth, take, drop, rest, last,
-                        concat, concatv, isdistinct, interpose, unique,
+                        get, concat, concatv, isdistinct, interpose, unique,
                         isiterable, remove, iterate, accumulate,
                         count, cons, take_nth)
 

cytoolz/cpython.pxd

@@ -0,0 +1,8 @@
+""" Additional bindings to Python's C-API.
+
+These differ from Cython's bindings in ``cpython``.
+"""
+from cpython.ref cimport PyObject
+
+cdef extern from "Python.h":
+    PyObject* PyObject_GetItem(object o, object key)

cytoolz/itertoolz/__init__.pxd

@@ -1,4 +1,4 @@
 from .core cimport (groupby, remove, concat, concatv, frequencies, interpose,
-                    first, second, nth, take, drop, rest, last, unique,
+                    first, second, nth, take, drop, rest, get, last, unique,
                     reduceby, isiterable, isdistinct, cons, iterate,
                     accumulate, count, take_nth)

cytoolz/itertoolz/__init__.py

@@ -1,4 +1,4 @@
 from .core import (groupby, remove, concat, concatv, frequencies, interpose,
-                   first, second, nth, take, drop, rest, last, unique,
+                   first, second, nth, take, drop, rest, get, last, unique,
                    reduceby, isiterable, isdistinct, cons, iterate,
                    accumulate, count, take_nth)

cytoolz/itertoolz/core.pxd

@@ -56,6 +56,9 @@ cpdef object last(object seq)
 cpdef object rest(object seq)
 
 
+cpdef object get(object ind, object seq, object default=*)
+
+
 cpdef inline object cons(object el, object seq)
 
 

cytoolz/itertoolz/core.pyx

@@ -1,10 +1,14 @@
 from cpython.dict cimport PyDict_Contains, PyDict_GetItem, PyDict_New, PyDict_SetItem
-from cpython.list cimport PyList_New, PyList_Append
-from cpython.ref cimport PyObject
+from cpython.exc cimport PyErr_Clear, PyErr_GivenExceptionMatches, PyErr_Occurred
+from cpython.list cimport PyList_Append, PyList_Check, PyList_New
+from cpython.ref cimport PyObject, Py_INCREF
 from cpython.sequence cimport PySequence_Check
 from cpython.set cimport PySet_Add, PySet_Contains
+from cpython.tuple cimport PyTuple_New, PyTuple_SET_ITEM
 from itertools import chain, islice
 
+from cytoolz.cpython cimport PyObject_GetItem
+
 
 concatv = chain
 concat = chain.from_iterable
@@ -329,6 +333,84 @@ cpdef object rest(object seq):
     return seq
 
 
+no_default = '__no__default__'
+
+
+cdef tuple _get_exceptions = (IndexError, KeyError, TypeError)
+
+
+cpdef object get(object ind, object seq, object default=no_default):
+    """ Get element in a sequence or dict
+
+    Provides standard indexing
+
+    >>> get(1, 'ABC')       # Same as 'ABC'[1]
+    'B'
+
+    Pass a list to get multiple values
+
+    >>> get([1, 2], 'ABC')  # ('ABC'[1], 'ABC'[2])
+    ('B', 'C')
+
+    Works on any value that supports indexing/getitem
+    For example here we see that it works with dictionaries
+
+    >>> phonebook = {'Alice':  '555-1234',
+    ...              'Bob':    '555-5678',
+    ...              'Charlie':'555-9999'}
+    >>> get('Alice', phonebook)
+    '555-1234'
+
+    >>> get(['Alice', 'Bob'], phonebook)
+    ('555-1234', '555-5678')
+
+    Provide a default for missing values
+
+    >>> get(['Alice', 'Dennis'], phonebook, None)
+    ('555-1234', None)
+
+    See Also:
+        pluck
+    """
+    cdef int i
+    cdef object val
+    cdef tuple result
+    cdef PyObject *obj
+    if PyList_Check(ind):
+        result = PyTuple_New(len(ind))
+        # List of indices, no default
+        if default is no_default:
+            for i, val in enumerate(ind):
+                val = seq[val]
+                Py_INCREF(val)
+                PyTuple_SET_ITEM(result, i, val)
+            return result
+
+        # List of indices with default
+        for i, val in enumerate(ind):
+            obj = PyObject_GetItem(seq, val)
+            if obj is NULL:
+                PyErr_Clear()
+                Py_INCREF(default)
+                PyTuple_SET_ITEM(result, i, default)
+            else:
+                val = <object>obj
+                Py_INCREF(val)
+                PyTuple_SET_ITEM(result, i, val)
+        return result
+
+    obj = PyObject_GetItem(seq, ind)
+    if obj is NULL:
+        val = <object>PyErr_Occurred()
+        if default is no_default:
+            raise val
+        if PyErr_GivenExceptionMatches(val, _get_exceptions):
+            PyErr_Clear()
+            return default
+        raise val
+    return <object>obj
+
+
 cpdef inline object cons(object el, object seq):
     """ Add el to beginning of (possibly infinite) sequence seq.
 

cytoolz/itertoolz/tests/test_core.py

@@ -5,7 +5,7 @@
                                     concat, concatv, unique,
                                     identity, isiterable,
                                     isdistinct, first, second,
-                                    nth, take, drop, interpose,
+                                    nth, take, drop, interpose, get,
                                     rest, last, cons, frequencies,
                                     reduceby, iterate, accumulate,
                                     count,
@@ -134,7 +134,6 @@ def test_take_nth():
     assert list(take_nth(2, 'ABCDE')) == list('ACE')
 
 
-'''
 def test_get():
     assert get(1, 'ABCDE') == 'B'
     assert list(get([1, 3], 'ABCDE')) == list('BD')
@@ -148,7 +147,6 @@ def test_get():
     assert raises(IndexError, lambda: get(10, 'ABC'))
     assert raises(KeyError, lambda: get(10, {'a': 1}))
     assert raises(TypeError, lambda: get({}, [1, 2, 3]))
-'''
 
 
 '''