概述
pandas中与库版本或依赖库版本相关的API主要有以下4个：
pandas.__version__：查看pandas简要版本信息。pandas.__git_version__：查看pandasgit版本信息。pandas._version.get_versions()：查看pandas详细版本信息。pandas.show_versions()：查看pandas及其依赖库的版本信息。
上述API的运行效果如下：
In [1]: import pandas as pd
In [2]: pd.__version__
Out[2]: '1.1.3'
In [3]: pd.__git_version__
Out[3]: 'db08276bc116c438d3fdee492026f8223584c477'
In [4]: pd._version.get_versions()
Out[4]:
{'dirty': False,
'error': None,
'full-revisionid': 'db08276bc116c438d3fdee492026f8223584c477',
'version': '1.1.3'}
In [5]: pd.show_versions(True)
{'system': {'commit': 'db08276bc116c438d3fdee492026f8223584c477', 'python': '3.7.2.final.0', 'python-bits': 64, 'OS': 'Windows', 'OS-release': '10', 'Version': '10.0.17763', 'machine': 'AMD64', 'processor': 'Intel64 Family 6 Model 94 Stepping 3, GenuineIntel', 'byteorder': 'little', 'LC_ALL': None, 'LANG': None, 'LOCALE': {'language-code': None, 'encoding': None}}, 'dependencies': {'pandas': '1.1.3', 'numpy': '1.20.1', 'pytz': '2019.2', 'dateutil': '2.8.0', 'pip': '19.3.1', 'setuptools': '51.1.0.post20201221', 'Cython': None, 'pytest': None, 'hypothesis': None, 'sphinx': None, 'blosc': None, 'feather': None, 'xlsxwriter': '3.0.1', 'lxml.etree': '4.4.2', 'html5lib': '1.1', 'pymysql': '0.9.3', 'psycopg2': None, 'jinja2': '2.11.2', 'IPython': '7.11.1', 'pandas_datareader': None, 'bs4': '4.9.3', 'bottleneck': None, 'fsspec': None, 'fastparquet': None, 'gcsfs': None, 'matplotlib': '3.4.1', 'numexpr': None, 'odfpy': None, 'openpyxl': '2.6.2', 'pandas_gbq': None, 'pyarrow': None, 'pytables': None, 'pyxlsb': None, 's3fs': None, 'scipy': '1.2.1', 'sqlalchemy': '1.4.18', 'tables': None, 'tabulate': None, 'xarray': None, 'xlrd': '1.2.0', 'xlwt': '1.3.0', 'numba': '0.52.0'}}
pandas._version.get_versions()、pandas.__version__和pandas.__git_version__原理
pandas._version.get_versions()
pandas._version.get_versions()源代码位于pandas包根目录下的_version.py。根据源码可知，该模块以JSON字符串形式存储版本信息，通过get_versions()返回字典形式的详细版本信息。
pandas/_version.py源码
from warnings import catch_warnings
with catch_warnings(record=True):
import json
import sys
version_json = '''
{
"dirty": false,
"error": null,
"full-revisionid": "db08276bc116c438d3fdee492026f8223584c477",
"version": "1.1.3"
}
''' # END VERSION_JSON
def get_versions():
return json.loads(version_json)
pandas.__version__和pandas.__git_version__
pandas.__version__和pandas.__git_version__源代码位于pandas包根目录下的__init__.py。根据源码可知，pandas.__version__和pandas.__git_version__源自于pandas._version.get_versions()的返回值。
生成这两个之后，删除了get_versions、v两个命名空间，因此不能使用pandas.get_versions()或pandas.v形式查看版本信息。
相关源码：
from ._version import get_versions
v = get_versions()
__version__ = v.get("closest-tag", v["version"])
__git_version__ = v.get("full-revisionid")
del get_versions, v
pandas.show_versions()原理
根据pandas包根目录下的__init__.py源码可知，通过from pandas.util._print_versions import show_versions重构命名空间，pandas.show_versions()的源代码位于pandas包util目录下的_print_versions.py模块。
根据源码可知，pandas.show_versions()的参数取值有3种情况：
False：打印输出类表格形式的依赖库版本信息。True：打印输出JSON字符串形式的依赖库版本信息。字符串：参数被认为是文件路径，版本信息以JSON形式写入该文件。
注意！pandas.show_versions()没有返回值即None。
pandas.show_versions()不同参数输出结果
In [5]: pd.show_versions(True)
{'system': {'commit': 'db08276bc116c438d3fdee492026f8223584c477', 'python': '3.7.2.final.0', 'python-bits': 64, 'OS': 'Windows', 'OS-release': '10', 'Version': '10.0.17763', 'machine': 'AMD64', 'processor': 'Intel64 Family 6 Model 94 Stepping 3, GenuineIntel', 'byteorder': 'little', 'LC_ALL': None, 'LANG': None, 'LOCALE': {'language-code': None, 'encoding': None}}, 'dependencies': {'pandas': '1.1.3', 'numpy': '1.20.1', 'pytz': '2019.2', 'dateutil': '2.8.0', 'pip': '19.3.1', 'setuptools': '51.1.0.post20201221', 'Cython': None, 'pytest': None, 'hypothesis': None, 'sphinx': None, 'blosc': None, 'feather': None, 'xlsxwriter': '3.0.1', 'lxml.etree': '4.4.2', 'html5lib': '1.1', 'pymysql': '0.9.3', 'psycopg2': None, 'jinja2': '2.11.2', 'IPython': '7.11.1', 'pandas_datareader': None, 'bs4': '4.9.3', 'bottleneck': None, 'fsspec': None, 'fastparquet': None, 'gcsfs': None, 'matplotlib': '3.4.1', 'numexpr': None, 'odfpy': None, 'openpyxl': '2.6.2', 'pandas_gbq': None, 'pyarrow': None, 'pytables': None, 'pyxlsb': None, 's3fs': None, 'scipy': '1.2.1', 'sqlalchemy': '1.4.18', 'tables': None, 'tabulate': None, 'xarray': None, 'xlrd': '1.2.0', 'xlwt': '1.3.0', 'numba': '0.52.0'}}
In [6]: pd.show_versions()
INSTALLED VERSIONS
------------------
commit : db08276bc116c438d3fdee492026f8223584c477
python : 3.7.2.final.0
python-bits : 64
OS : Windows
OS-release : 10
Version : 10.0.17763
machine : AMD64
processor : Intel64 Family 6 Model 94 Stepping 3, GenuineIntel
byteorder : little
LC_ALL : None
LANG : None
LOCALE : None.None
pandas : 1.1.3
numpy : 1.20.1
pytz : 2019.2
dateutil : 2.8.0
pip : 19.3.1
setuptools : 51.1.0.post20201221
Cython : None
pytest : None
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : 3.0.1
lxml.etree : 4.4.2
html5lib : 1.1
pymysql : 0.9.3
psycopg2 : None
jinja2 : 2.11.2
IPython : 7.11.1
pandas_datareader: None
bs4 : 4.9.3
bottleneck : None
fsspec : None
fastparquet : None
gcsfs : None
matplotlib : 3.4.1
numexpr : None
odfpy : None
openpyxl : 2.6.2
pandas_gbq : None
pyarrow : None
pytables : None
pyxlsb : None
s3fs : None
scipy : 1.2.1
sqlalchemy : 1.4.18
tables : None
tabulate : None
xarray : None
xlrd : 1.2.0
xlwt : 1.3.0
numba : 0.52.0
In [7]: pd.show_versions("./version.json")
相关源码：
def show_versions(as_json: Union[str, bool] = False) -> None:
"""
Provide useful information, important for bug reports.
It comprises info about hosting operation system, pandas version,
and versions of other installed relative packages.
Parameters
----------
as_json : str or bool, default False
* If False, outputs info in a human readable form to the console.
* If str, it will be considered as a path to a file.
Info will be written to that file in JSON format.
* If True, outputs info in JSON format to the console.
"""
sys_info = _get_sys_info()
deps = _get_dependency_info()
if as_json:
j = dict(system=sys_info, dependencies=deps)
if as_json is True:
print(j)
else:
assert isinstance(as_json, str) # needed for mypy
with codecs.open(as_json, "wb", encoding="utf8") as f:
json.dump(j, f, indent=2)
else:
assert isinstance(sys_info["LOCALE"], dict) # needed for mypy
language_code = sys_info["LOCALE"]["language-code"]
encoding = sys_info["LOCALE"]["encoding"]
sys_info["LOCALE"] = f"{language_code}.{encoding}"
maxlen = max(len(x) for x in deps)
print("\nINSTALLED VERSIONS")
print("------------------")
for k, v in sys_info.items():
print(f"{k:<{maxlen}}: {v}")
print("")
for k, v in deps.items():
print(f"{k:<{maxlen}}: {v}")