Edit File: test_defchararray.py
import pytest import numpy as np from numpy.core.multiarray import _vec_string from numpy.testing import ( assert_, assert_equal, assert_array_equal, assert_raises, assert_raises_regex ) kw_unicode_true = {'unicode': True} # make 2to3 work properly kw_unicode_false = {'unicode': False} class TestBasic: def test_from_object_array(self): A = np.array([['abc', 2], ['long ', '0123456789']], dtype='O') B = np.char.array(A) assert_equal(B.dtype.itemsize, 10) assert_array_equal(B, [[b'abc', b'2'], [b'long', b'0123456789']]) def test_from_object_array_unicode(self): A = np.array([['abc', 'Sigma \u03a3'], ['long ', '0123456789']], dtype='O') assert_raises(ValueError, np.char.array, (A,)) B = np.char.array(A, **kw_unicode_true) assert_equal(B.dtype.itemsize, 10 * np.array('a', 'U').dtype.itemsize) assert_array_equal(B, [['abc', 'Sigma \u03a3'], ['long', '0123456789']]) def test_from_string_array(self): A = np.array([[b'abc', b'foo'], [b'long ', b'0123456789']]) assert_equal(A.dtype.type, np.bytes_) B = np.char.array(A) assert_array_equal(B, A) assert_equal(B.dtype, A.dtype) assert_equal(B.shape, A.shape) B[0, 0] = 'changed' assert_(B[0, 0] != A[0, 0]) C = np.char.asarray(A) assert_array_equal(C, A) assert_equal(C.dtype, A.dtype) C[0, 0] = 'changed again' assert_(C[0, 0] != B[0, 0]) assert_(C[0, 0] == A[0, 0]) def test_from_unicode_array(self): A = np.array([['abc', 'Sigma \u03a3'], ['long ', '0123456789']]) assert_equal(A.dtype.type, np.str_) B = np.char.array(A) assert_array_equal(B, A) assert_equal(B.dtype, A.dtype) assert_equal(B.shape, A.shape) B = np.char.array(A, **kw_unicode_true) assert_array_equal(B, A) assert_equal(B.dtype, A.dtype) assert_equal(B.shape, A.shape) def fail(): np.char.array(A, **kw_unicode_false) assert_raises(UnicodeEncodeError, fail) def test_unicode_upconvert(self): A = np.char.array(['abc']) B = np.char.array(['\u03a3']) assert_(issubclass((A + B).dtype.type, np.str_)) def test_from_string(self): A = np.char.array(b'abc') assert_equal(len(A), 1) assert_equal(len(A[0]), 3) assert_(issubclass(A.dtype.type, np.bytes_)) def test_from_unicode(self): A = np.char.array('\u03a3') assert_equal(len(A), 1) assert_equal(len(A[0]), 1) assert_equal(A.itemsize, 4) assert_(issubclass(A.dtype.type, np.str_)) class TestVecString: def test_non_existent_method(self): def fail(): _vec_string('a', np.bytes_, 'bogus') assert_raises(AttributeError, fail) def test_non_string_array(self): def fail(): _vec_string(1, np.bytes_, 'strip') assert_raises(TypeError, fail) def test_invalid_args_tuple(self): def fail(): _vec_string(['a'], np.bytes_, 'strip', 1) assert_raises(TypeError, fail) def test_invalid_type_descr(self): def fail(): _vec_string(['a'], 'BOGUS', 'strip') assert_raises(TypeError, fail) def test_invalid_function_args(self): def fail(): _vec_string(['a'], np.bytes_, 'strip', (1,)) assert_raises(TypeError, fail) def test_invalid_result_type(self): def fail(): _vec_string(['a'], np.int_, 'strip') assert_raises(TypeError, fail) def test_broadcast_error(self): def fail(): _vec_string([['abc', 'def']], np.int_, 'find', (['a', 'd', 'j'],)) assert_raises(ValueError, fail) class TestWhitespace: def setup_method(self): self.A = np.array([['abc ', '123 '], ['789 ', 'xyz ']]).view(np.chararray) self.B = np.array([['abc', '123'], ['789', 'xyz']]).view(np.chararray) def test1(self): assert_(np.all(self.A == self.B)) assert_(np.all(self.A >= self.B)) assert_(np.all(self.A <= self.B)) assert_(not np.any(self.A > self.B)) assert_(not np.any(self.A < self.B)) assert_(not np.any(self.A != self.B)) class TestChar: def setup_method(self): self.A = np.array('abc1', dtype='c').view(np.chararray) def test_it(self): assert_equal(self.A.shape, (4,)) assert_equal(self.A.upper()[:2].tobytes(), b'AB') class TestComparisons: def setup_method(self): self.A = np.array([['abc', '123'], ['789', 'xyz']]).view(np.chararray) self.B = np.array([['efg', '123 '], ['051', 'tuv']]).view(np.chararray) def test_not_equal(self): assert_array_equal((self.A != self.B), [[True, False], [True, True]]) def test_equal(self): assert_array_equal((self.A == self.B), [[False, True], [False, False]]) def test_greater_equal(self): assert_array_equal((self.A >= self.B), [[False, True], [True, True]]) def test_less_equal(self): assert_array_equal((self.A <= self.B), [[True, True], [False, False]]) def test_greater(self): assert_array_equal((self.A > self.B), [[False, False], [True, True]]) def test_less(self): assert_array_equal((self.A < self.B), [[True, False], [False, False]]) def test_type(self): out1 = np.char.equal(self.A, self.B) out2 = np.char.equal('a', 'a') assert_(isinstance(out1, np.ndarray)) assert_(isinstance(out2, np.ndarray)) class TestComparisonsMixed1(TestComparisons): """Ticket #1276""" def setup_method(self): TestComparisons.setup_method(self) self.B = np.array([['efg', '123 '], ['051', 'tuv']], np.str_).view(np.chararray) class TestComparisonsMixed2(TestComparisons): """Ticket #1276""" def setup_method(self): TestComparisons.setup_method(self) self.A = np.array([['abc', '123'], ['789', 'xyz']], np.str_).view(np.chararray) class TestInformation: def setup_method(self): self.A = np.array([[' abc ', ''], ['12345', 'MixedCase'], ['123 \t 345 \0 ', 'UPPER']]).view(np.chararray) self.B = np.array([[' \u03a3 ', ''], ['12345', 'MixedCase'], ['123 \t 345 \0 ', 'UPPER']]).view(np.chararray) def test_len(self): assert_(issubclass(np.char.str_len(self.A).dtype.type, np.integer)) assert_array_equal(np.char.str_len(self.A), [[5, 0], [5, 9], [12, 5]]) assert_array_equal(np.char.str_len(self.B), [[3, 0], [5, 9], [12, 5]]) def test_count(self): assert_(issubclass(self.A.count('').dtype.type, np.integer)) assert_array_equal(self.A.count('a'), [[1, 0], [0, 1], [0, 0]]) assert_array_equal(self.A.count('123'), [[0, 0], [1, 0], [1, 0]]) # Python doesn't seem to like counting NULL characters # assert_array_equal(self.A.count('\0'), [[0, 0], [0, 0], [1, 0]]) assert_array_equal(self.A.count('a', 0, 2), [[1, 0], [0, 0], [0, 0]]) assert_array_equal(self.B.count('a'), [[0, 0], [0, 1], [0, 0]]) assert_array_equal(self.B.count('123'), [[0, 0], [1, 0], [1, 0]]) # assert_array_equal(self.B.count('\0'), [[0, 0], [0, 0], [1, 0]]) def test_endswith(self): assert_(issubclass(self.A.endswith('').dtype.type, np.bool_)) assert_array_equal(self.A.endswith(' '), [[1, 0], [0, 0], [1, 0]]) assert_array_equal(self.A.endswith('3', 0, 3), [[0, 0], [1, 0], [1, 0]]) def fail(): self.A.endswith('3', 'fdjk') assert_raises(TypeError, fail) def test_find(self): assert_(issubclass(self.A.find('a').dtype.type, np.integer)) assert_array_equal(self.A.find('a'), [[1, -1], [-1, 6], [-1, -1]]) assert_array_equal(self.A.find('3'), [[-1, -1], [2, -1], [2, -1]]) assert_array_equal(self.A.find('a', 0, 2), [[1, -1], [-1, -1], [-1, -1]]) assert_array_equal(self.A.find(['1', 'P']), [[-1, -1], [0, -1], [0, 1]]) def test_index(self): def fail(): self.A.index('a') assert_raises(ValueError, fail) assert_(np.char.index('abcba', 'b') == 1) assert_(issubclass(np.char.index('abcba', 'b').dtype.type, np.integer)) def test_isalnum(self): assert_(issubclass(self.A.isalnum().dtype.type, np.bool_)) assert_array_equal(self.A.isalnum(), [[False, False], [True, True], [False, True]]) def test_isalpha(self): assert_(issubclass(self.A.isalpha().dtype.type, np.bool_)) assert_array_equal(self.A.isalpha(), [[False, False], [False, True], [False, True]]) def test_isdigit(self): assert_(issubclass(self.A.isdigit().dtype.type, np.bool_)) assert_array_equal(self.A.isdigit(), [[False, False], [True, False], [False, False]]) def test_islower(self): assert_(issubclass(self.A.islower().dtype.type, np.bool_)) assert_array_equal(self.A.islower(), [[True, False], [False, False], [False, False]]) def test_isspace(self): assert_(issubclass(self.A.isspace().dtype.type, np.bool_)) assert_array_equal(self.A.isspace(), [[False, False], [False, False], [False, False]]) def test_istitle(self): assert_(issubclass(self.A.istitle().dtype.type, np.bool_)) assert_array_equal(self.A.istitle(), [[False, False], [False, False], [False, False]]) def test_isupper(self): assert_(issubclass(self.A.isupper().dtype.type, np.bool_)) assert_array_equal(self.A.isupper(), [[False, False], [False, False], [False, True]]) def test_rfind(self): assert_(issubclass(self.A.rfind('a').dtype.type, np.integer)) assert_array_equal(self.A.rfind('a'), [[1, -1], [-1, 6], [-1, -1]]) assert_array_equal(self.A.rfind('3'), [[-1, -1], [2, -1], [6, -1]]) assert_array_equal(self.A.rfind('a', 0, 2), [[1, -1], [-1, -1], [-1, -1]]) assert_array_equal(self.A.rfind(['1', 'P']), [[-1, -1], [0, -1], [0, 2]]) def test_rindex(self): def fail(): self.A.rindex('a') assert_raises(ValueError, fail) assert_(np.char.rindex('abcba', 'b') == 3) assert_(issubclass(np.char.rindex('abcba', 'b').dtype.type, np.integer)) def test_startswith(self): assert_(issubclass(self.A.startswith('').dtype.type, np.bool_)) assert_array_equal(self.A.startswith(' '), [[1, 0], [0, 0], [0, 0]]) assert_array_equal(self.A.startswith('1', 0, 3), [[0, 0], [1, 0], [1, 0]]) def fail(): self.A.startswith('3', 'fdjk') assert_raises(TypeError, fail) class TestMethods: def setup_method(self): self.A = np.array([[' abc ', ''], ['12345', 'MixedCase'], ['123 \t 345 \0 ', 'UPPER']], dtype='S').view(np.chararray) self.B = np.array([[' \u03a3 ', ''], ['12345', 'MixedCase'], ['123 \t 345 \0 ', 'UPPER']]).view(np.chararray) def test_capitalize(self): tgt = [[b' abc ', b''], [b'12345', b'Mixedcase'], [b'123 \t 345 \0 ', b'Upper']] assert_(issubclass(self.A.capitalize().dtype.type, np.bytes_)) assert_array_equal(self.A.capitalize(), tgt) tgt = [[' \u03c3 ', ''], ['12345', 'Mixedcase'], ['123 \t 345 \0 ', 'Upper']] assert_(issubclass(self.B.capitalize().dtype.type, np.str_)) assert_array_equal(self.B.capitalize(), tgt) def test_center(self): assert_(issubclass(self.A.center(10).dtype.type, np.bytes_)) C = self.A.center([10, 20]) assert_array_equal(np.char.str_len(C), [[10, 20], [10, 20], [12, 20]]) C = self.A.center(20, b'#') assert_(np.all(C.startswith(b'#'))) assert_(np.all(C.endswith(b'#'))) C = np.char.center(b'FOO', [[10, 20], [15, 8]]) tgt = [[b' FOO ', b' FOO '], [b' FOO ', b' FOO ']] assert_(issubclass(C.dtype.type, np.bytes_)) assert_array_equal(C, tgt) def test_decode(self): A = np.char.array([b'\\u03a3']) assert_(A.decode('unicode-escape')[0] == '\u03a3') def test_encode(self): B = self.B.encode('unicode_escape') assert_(B[0][0] == str(' \\u03a3 ').encode('latin1')) def test_expandtabs(self): T = self.A.expandtabs() assert_(T[2, 0] == b'123 345 \0') def test_join(self): # NOTE: list(b'123') == [49, 50, 51] # so that b','.join(b'123') results to an error on Py3 A0 = self.A.decode('ascii') A = np.char.join([',', '#'], A0) assert_(issubclass(A.dtype.type, np.str_)) tgt = np.array([[' ,a,b,c, ', ''], ['1,2,3,4,5', 'M#i#x#e#d#C#a#s#e'], ['1,2,3, ,\t, ,3,4,5, ,\x00, ', 'U#P#P#E#R']]) assert_array_equal(np.char.join([',', '#'], A0), tgt) def test_ljust(self): assert_(issubclass(self.A.ljust(10).dtype.type, np.bytes_)) C = self.A.ljust([10, 20]) assert_array_equal(np.char.str_len(C), [[10, 20], [10, 20], [12, 20]]) C = self.A.ljust(20, b'#') assert_array_equal(C.startswith(b'#'), [ [False, True], [False, False], [False, False]]) assert_(np.all(C.endswith(b'#'))) C = np.char.ljust(b'FOO', [[10, 20], [15, 8]]) tgt = [[b'FOO ', b'FOO '], [b'FOO ', b'FOO ']] assert_(issubclass(C.dtype.type, np.bytes_)) assert_array_equal(C, tgt) def test_lower(self): tgt = [[b' abc ', b''], [b'12345', b'mixedcase'], [b'123 \t 345 \0 ', b'upper']] assert_(issubclass(self.A.lower().dtype.type, np.bytes_)) assert_array_equal(self.A.lower(), tgt) tgt = [[' \u03c3 ', ''], ['12345', 'mixedcase'], ['123 \t 345 \0 ', 'upper']] assert_(issubclass(self.B.lower().dtype.type, np.str_)) assert_array_equal(self.B.lower(), tgt) def test_lstrip(self): tgt = [[b'abc ', b''], [b'12345', b'MixedCase'], [b'123 \t 345 \0 ', b'UPPER']] assert_(issubclass(self.A.lstrip().dtype.type, np.bytes_)) assert_array_equal(self.A.lstrip(), tgt) tgt = [[b' abc', b''], [b'2345', b'ixedCase'], [b'23 \t 345 \x00', b'UPPER']] assert_array_equal(self.A.lstrip([b'1', b'M']), tgt) tgt = [['\u03a3 ', ''], ['12345', 'MixedCase'], ['123 \t 345 \0 ', 'UPPER']] assert_(issubclass(self.B.lstrip().dtype.type, np.str_)) assert_array_equal(self.B.lstrip(), tgt) def test_partition(self): P = self.A.partition([b'3', b'M']) tgt = [[(b' abc ', b'', b''), (b'', b'', b'')], [(b'12', b'3', b'45'), (b'', b'M', b'ixedCase')], [(b'12', b'3', b' \t 345 \0 '), (b'UPPER', b'', b'')]] assert_(issubclass(P.dtype.type, np.bytes_)) assert_array_equal(P, tgt) def test_replace(self): R = self.A.replace([b'3', b'a'], [b'##########', b'@']) tgt = [[b' abc ', b''], [b'12##########45', b'MixedC@se'], [b'12########## \t ##########45 \x00', b'UPPER']] assert_(issubclass(R.dtype.type, np.bytes_)) assert_array_equal(R, tgt) def test_rjust(self): assert_(issubclass(self.A.rjust(10).dtype.type, np.bytes_)) C = self.A.rjust([10, 20]) assert_array_equal(np.char.str_len(C), [[10, 20], [10, 20], [12, 20]]) C = self.A.rjust(20, b'#') assert_(np.all(C.startswith(b'#'))) assert_array_equal(C.endswith(b'#'), [[False, True], [False, False], [False, False]]) C = np.char.rjust(b'FOO', [[10, 20], [15, 8]]) tgt = [[b' FOO', b' FOO'], [b' FOO', b' FOO']] assert_(issubclass(C.dtype.type, np.bytes_)) assert_array_equal(C, tgt) def test_rpartition(self): P = self.A.rpartition([b'3', b'M']) tgt = [[(b'', b'', b' abc '), (b'', b'', b'')], [(b'12', b'3', b'45'), (b'', b'M', b'ixedCase')], [(b'123 \t ', b'3', b'45 \0 '), (b'', b'', b'UPPER')]] assert_(issubclass(P.dtype.type, np.bytes_)) assert_array_equal(P, tgt) def test_rsplit(self): A = self.A.rsplit(b'3') tgt = [[[b' abc '], [b'']], [[b'12', b'45'], [b'MixedCase']], [[b'12', b' \t ', b'45 \x00 '], [b'UPPER']]] assert_(issubclass(A.dtype.type, np.object_)) assert_equal(A.tolist(), tgt) def test_rstrip(self): assert_(issubclass(self.A.rstrip().dtype.type, np.bytes_)) tgt = [[b' abc', b''], [b'12345', b'MixedCase'], [b'123 \t 345', b'UPPER']] assert_array_equal(self.A.rstrip(), tgt) tgt = [[b' abc ', b''], [b'1234', b'MixedCase'], [b'123 \t 345 \x00', b'UPP'] ] assert_array_equal(self.A.rstrip([b'5', b'ER']), tgt) tgt = [[' \u03a3', ''], ['12345', 'MixedCase'], ['123 \t 345', 'UPPER']] assert_(issubclass(self.B.rstrip().dtype.type, np.str_)) assert_array_equal(self.B.rstrip(), tgt) def test_strip(self): tgt = [[b'abc', b''], [b'12345', b'MixedCase'], [b'123 \t 345', b'UPPER']] assert_(issubclass(self.A.strip().dtype.type, np.bytes_)) assert_array_equal(self.A.strip(), tgt) tgt = [[b' abc ', b''], [b'234', b'ixedCas'], [b'23 \t 345 \x00', b'UPP']] assert_array_equal(self.A.strip([b'15', b'EReM']), tgt) tgt = [['\u03a3', ''], ['12345', 'MixedCase'], ['123 \t 345', 'UPPER']] assert_(issubclass(self.B.strip().dtype.type, np.str_)) assert_array_equal(self.B.strip(), tgt) def test_split(self): A = self.A.split(b'3') tgt = [ [[b' abc '], [b'']], [[b'12', b'45'], [b'MixedCase']], [[b'12', b' \t ', b'45 \x00 '], [b'UPPER']]] assert_(issubclass(A.dtype.type, np.object_)) assert_equal(A.tolist(), tgt) def test_splitlines(self): A = np.char.array(['abc\nfds\nwer']).splitlines() assert_(issubclass(A.dtype.type, np.object_)) assert_(A.shape == (1,)) assert_(len(A[0]) == 3) def test_swapcase(self): tgt = [[b' ABC ', b''], [b'12345', b'mIXEDcASE'], [b'123 \t 345 \0 ', b'upper']] assert_(issubclass(self.A.swapcase().dtype.type, np.bytes_)) assert_array_equal(self.A.swapcase(), tgt) tgt = [[' \u03c3 ', ''], ['12345', 'mIXEDcASE'], ['123 \t 345 \0 ', 'upper']] assert_(issubclass(self.B.swapcase().dtype.type, np.str_)) assert_array_equal(self.B.swapcase(), tgt) def test_title(self): tgt = [[b' Abc ', b''], [b'12345', b'Mixedcase'], [b'123 \t 345 \0 ', b'Upper']] assert_(issubclass(self.A.title().dtype.type, np.bytes_)) assert_array_equal(self.A.title(), tgt) tgt = [[' \u03a3 ', ''], ['12345', 'Mixedcase'], ['123 \t 345 \0 ', 'Upper']] assert_(issubclass(self.B.title().dtype.type, np.str_)) assert_array_equal(self.B.title(), tgt) def test_upper(self): tgt = [[b' ABC ', b''], [b'12345', b'MIXEDCASE'], [b'123 \t 345 \0 ', b'UPPER']] assert_(issubclass(self.A.upper().dtype.type, np.bytes_)) assert_array_equal(self.A.upper(), tgt) tgt = [[' \u03a3 ', ''], ['12345', 'MIXEDCASE'], ['123 \t 345 \0 ', 'UPPER']] assert_(issubclass(self.B.upper().dtype.type, np.str_)) assert_array_equal(self.B.upper(), tgt) def test_isnumeric(self): def fail(): self.A.isnumeric() assert_raises(TypeError, fail) assert_(issubclass(self.B.isnumeric().dtype.type, np.bool_)) assert_array_equal(self.B.isnumeric(), [ [False, False], [True, False], [False, False]]) def test_isdecimal(self): def fail(): self.A.isdecimal() assert_raises(TypeError, fail) assert_(issubclass(self.B.isdecimal().dtype.type, np.bool_)) assert_array_equal(self.B.isdecimal(), [ [False, False], [True, False], [False, False]]) class TestOperations: def setup_method(self): self.A = np.array([['abc', '123'], ['789', 'xyz']]).view(np.chararray) self.B = np.array([['efg', '456'], ['051', 'tuv']]).view(np.chararray) def test_add(self): AB = np.array([['abcefg', '123456'], ['789051', 'xyztuv']]).view(np.chararray) assert_array_equal(AB, (self.A + self.B)) assert_(len((self.A + self.B)[0][0]) == 6) def test_radd(self): QA = np.array([['qabc', 'q123'], ['q789', 'qxyz']]).view(np.chararray) assert_array_equal(QA, ('q' + self.A)) def test_mul(self): A = self.A for r in (2, 3, 5, 7, 197): Ar = np.array([[A[0, 0]*r, A[0, 1]*r], [A[1, 0]*r, A[1, 1]*r]]).view(np.chararray) assert_array_equal(Ar, (self.A * r)) for ob in [object(), 'qrs']: with assert_raises_regex(ValueError, 'Can only multiply by integers'): A*ob def test_rmul(self): A = self.A for r in (2, 3, 5, 7, 197): Ar = np.array([[A[0, 0]*r, A[0, 1]*r], [A[1, 0]*r, A[1, 1]*r]]).view(np.chararray) assert_array_equal(Ar, (r * self.A)) for ob in [object(), 'qrs']: with assert_raises_regex(ValueError, 'Can only multiply by integers'): ob * A def test_mod(self): """Ticket #856""" F = np.array([['%d', '%f'], ['%s', '%r']]).view(np.chararray) C = np.array([[3, 7], [19, 1]]) FC = np.array([['3', '7.000000'], ['19', '1']]).view(np.chararray) assert_array_equal(FC, F % C) A = np.array([['%.3f', '%d'], ['%s', '%r']]).view(np.chararray) A1 = np.array([['1.000', '1'], ['1', '1']]).view(np.chararray) assert_array_equal(A1, (A % 1)) A2 = np.array([['1.000', '2'], ['3', '4']]).view(np.chararray) assert_array_equal(A2, (A % [[1, 2], [3, 4]])) def test_rmod(self): assert_(("%s" % self.A) == str(self.A)) assert_(("%r" % self.A) == repr(self.A)) for ob in [42, object()]: with assert_raises_regex( TypeError, "unsupported operand type.* and 'chararray'"): ob % self.A def test_slice(self): """Regression test for https://github.com/numpy/numpy/issues/5982""" arr = np.array([['abc ', 'def '], ['geh ', 'ijk ']], dtype='S4').view(np.chararray) sl1 = arr[:] assert_array_equal(sl1, arr) assert_(sl1.base is arr) assert_(sl1.base.base is arr.base) sl2 = arr[:, :] assert_array_equal(sl2, arr) assert_(sl2.base is arr) assert_(sl2.base.base is arr.base) assert_(arr[0, 0] == b'abc') def test_empty_indexing(): """Regression test for ticket 1948.""" # Check that indexing a chararray with an empty list/array returns an # empty chararray instead of a chararray with a single empty string in it. s = np.chararray((4,)) assert_(s[[]].size == 0) @pytest.mark.parametrize(["dt1", "dt2"], [("S", "U"), ("U", "S"), ("S", "O"), ("U", "O"), ("S", "d"), ("S", "V")]) def test_add_types(dt1, dt2): arr1 = np.array([1234234], dtype=dt1) # If the following fails, e.g. use a number and test "V" explicitly arr2 = np.array([b"423"], dtype=dt2) with pytest.raises(TypeError, match=f".*same dtype kind.*{arr1.dtype}.*{arr2.dtype}"): np.char.add(arr1, arr2)