BUG: Trouble with r/l/strip when stripping a non-ASCII character from a StringDType #26915
Description
Describe the issue:
It seems rstrip can't strip a Unicode character such as 'μ' from the string "λμ":
In [89]: a = np.array(["abc", "λμ"], dtype=np.dtype('T'))
In [90]: a
Out[90]: array(['abc', 'λμ'], dtype=StringDType())
Try to rstrip 'μ':
In [91]: np.strings.rstrip(a, 'μ')
Out[91]: array(['abc', 'λμ'], dtype=StringDType())
It is still there.
Pass a as chars; this should strip everything:
In [92]: np.strings.rstrip(a, a)
Out[92]: array(['', 'λμ'], dtype=StringDType())
Nope.
Try with strip instead of rstrip; 'λ' is removed, but 'μ' remains:
In [93]: np.strings.strip(a, a)
Out[93]: array(['', 'μ'], dtype=StringDType())
Python and NumPy Versions:
In [102]: import sys, numpy; print(numpy.__version__); print(sys.version)
2.1.0.dev0+git20240711.abeca76
3.12.4 (main, Jul 4 2024, 20:00:06) [GCC 11.4.0]
Runtime Environment:
[{'numpy_version': '2.1.0.dev0+git20240711.abeca76',
'python': '3.12.4 (main, Jul 4 2024, 20:00:06) [GCC 11.4.0]',
'uname': uname_result(system='Linux', node='pop-os', release='6.9.3-76060903-generic', version='#202405300957~1718348209~22.04~7817b67 SMP PREEMPT_DYNAMIC Mon J', machine='x86_64')},
{'simd_extensions': {'baseline': ['SSE', 'SSE2', 'SSE3'],
'found': ['SSSE3',
'SSE41',
'POPCNT',
'SSE42',
'AVX',
'F16C',
'FMA3',
'AVX2'],
'not_found': ['AVX512F',
'AVX512CD',
'AVX512_KNL',
'AVX512_KNM',
'AVX512_SKX',
'AVX512_CLX',
'AVX512_CNL',
'AVX512_ICL']}},
{'architecture': 'Zen',
'filepath': '/usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblasp-r0.3.20.so',
'internal_api': 'openblas',
'num_threads': 24,
'prefix': 'libopenblas',
'threading_layer': 'pthreads',
'user_api': 'blas',
'version': '0.3.20'}]