当我执行conda install spacy --no-update-dependencies时，conda要比我执行conda install spacy时进行更多的更新。为什么？
但是，我读了https://conda.io/docs/commands/conda-install.html：
--no-update-dependencies, --no-update-deps Don't update dependencies (default: False).
我本以为添加--no-update-dependencies会导致使用conda进行的更新更少。
conda install spacy：
C:\Users\john\AppData\Local\Continuum\Anaconda3\Scripts>conda install spacy --update-dependencies
Fetching package metadata .............
Solving package specifications: .
Package plan for installation in environment C:\Users\john\AppData\Local\Continuum\Anaconda3:
The following NEW packages will be INSTALLED:
cymem: 1.31.2-py36_vc14_0 conda-forge [vc14]
dill: 0.2.6-py36_0 conda-forge
ftfy: 4.4.2-py36_0 conda-forge
murmurhash: 0.26.4-py36_vc14_0 conda-forge [vc14]
plac: 0.9.6-py36_0
preshed: 1.0.0-py36_vc14_0 conda-forge [vc14]
pyreadline: 2.1-py36_0
regex: 2017.04.05-py36_0 conda-forge
spacy: 1.8.2-np112py36_vc14_0 conda-forge [vc14]
termcolor: 1.1.0-py36_1 conda-forge
thinc: 6.5.2-np112py36_vc14_0 conda-forge [vc14]
tqdm: 4.14.0-py36_0 conda-forge
ujson: 1.35-py36_0
The following packages will be UPDATED:
conda: 4.3.21-py36_0 --> 4.3.22-py36_0 conda-forge
The following packages will be SUPERSEDED by a higher-priority channel:
conda-env: 2.6.0-0 file:///C:/Users/john/AppData/Local/Continuum/Anaconda3/Scripts --> 2.6.0-0 conda-forge
Proceed ([y]/n)?
conda install spacy --no-update-dependencies：
C:\Users\john\AppData\Local\Continuum\Anaconda3\Scripts>conda install spacy --no-update-dependencies
Fetching package metadata .............
Solving package specifications: .
Package plan for installation in environment C:\Users\john\AppData\Local\Continuum\Anaconda3:
The following NEW packages will be INSTALLED:
boto3: 1.4.4-py36_0 conda-forge
botocore: 1.5.55-py36_0 conda-forge
cymem: 1.31.2-py36_vc14_0 conda-forge [vc14]
dill: 0.2.6-py36_0 conda-forge
ftfy: 4.4.2-py36_0 conda-forge
imageio: 2.2.0-py36_0 conda-forge
jmespath: 0.9.3-py36_0 conda-forge
libiconv: 1.14-vc14_4 conda-forge [vc14]
libxml2: 2.9.4-vc14_4 conda-forge [vc14]
libxslt: 1.1.29-vc14_5 conda-forge [vc14]
mccabe: 0.6.1-py36_0 conda-forge
murmurhash: 0.26.4-py36_vc14_0 conda-forge [vc14]
pandoc: 1.19.2-0 conda-forge
plac: 0.9.6-py36_0
preshed: 1.0.0-py36_vc14_0 conda-forge [vc14]
pyreadline: 2.1-py36_0
regex: 2017.04.05-py36_0 conda-forge
s3fs: 0.1.1-py36_0 conda-forge
s3transfer: 0.1.10-py36_1 conda-forge
spacy: 1.8.2-np112py36_vc14_0 conda-forge [vc14]
termcolor: 1.1.0-py36_1 conda-forge
thinc: 6.5.2-np112py36_vc14_0 conda-forge [vc14]
tqdm: 4.14.0-py36_0 conda-forge
ujson: 1.35-py36_0
vc: 14-0 conda-forge
webencodings: 0.5-py36_0 conda-forge
yaml: 0.1.6-vc14_0 conda-forge [vc14]
The following packages will be UPDATED:
conda: 4.3.21-py36_0 --> 4.3.22-py36_0 conda-forge
The following packages will be SUPERSEDED by a higher-priority channel:
alabaster: 0.7.10-py36_0 --> 0.7.10-py36_0 conda-forge
anaconda-client: 1.6.3-py36_0 --> 1.6.3-py36_0 conda-forge
asn1crypto: 0.22.0-py36_0 --> 0.22.0-py36_0 conda-forge
astropy: 1.3.2-np112py36_0 --> 1.3.2-np112py36_0 conda-forge
bleach: 1.5.0-py36_0 --> 1.5.0-py36_0 conda-forge
cffi: 1.10.0-py36_0 --> 1.10.0-py36_0 conda-forge
click: 6.7-py36_0 --> 6.7-py36_0 conda-forge
colorama: 0.3.9-py36_0 --> 0.3.9-py36_0 conda-forge
conda-env: 2.6.0-0 file:///C:/Users/john/AppData/Local/Continuum/Anaconda3/Scripts --> 2.6.0-0 conda-forge
contextlib2: 0.5.5-py36_0 --> 0.5.5-py36_0 conda-forge
curl: 7.52.1-vc14_0 [vc14] --> 7.52.1-vc14_0 conda-forge [vc14]
cycler: 0.10.0-py36_0 --> 0.10.0-py36_0 conda-forge
cython: 0.25.2-py36_0 --> 0.25.2-py36_0 conda-forge
cytoolz: 0.8.2-py36_0 --> 0.8.2-py36_0 conda-forge
decorator: 4.0.11-py36_0 --> 4.0.11-py36_0 conda-forge
distributed: 1.16.3-py36_0 --> 1.16.3-py36_0 conda-forge
docutils: 0.13.1-py36_0 --> 0.13.1-py36_0 conda-forge
entrypoints: 0.2.2-py36_1 --> 0.2.2-py36_1 conda-forge
et_xmlfile: 1.0.1-py36_0 --> 1.0.1-py36_0 conda-forge
greenlet: 0.4.12-py36_0 --> 0.4.12-py36_0 conda-forge
html5lib: 0.999-py36_0 --> 0.999-py36_0 conda-forge
idna: 2.5-py36_0 --> 2.5-py36_0 conda-forge
imagesize: 0.7.1-py36_0 --> 0.7.1-py36_0 conda-forge
ipykernel: 4.6.1-py36_0 --> 4.6.1-py36_0 conda-forge
ipython: 5.3.0-py36_0 --> 5.3.0-py36_0 conda-forge
ipython_genutils: 0.2.0-py36_0 --> 0.2.0-py36_0 conda-forge
ipywidgets: 6.0.0-py36_0 --> 6.0.0-py36_0 conda-forge
isort: 4.2.5-py36_0 --> 4.2.5-py36_0 conda-forge
jdcal: 1.3-py36_0 --> 1.3-py36_0 conda-forge
jpeg: 9b-vc14_0 [vc14] --> 9b-vc14_0 conda-forge [vc14]
jupyter_client: 5.0.1-py36_0 --> 5.0.1-py36_0 conda-forge
jupyter_console: 5.1.0-py36_0 --> 5.1.0-py36_0 conda-forge
jupyter_core: 4.3.0-py36_0 --> 4.3.0-py36_0 conda-forge
lazy-object-proxy: 1.2.2-py36_0 --> 1.2.2-py36_0 conda-forge
locket: 0.2.0-py36_1 --> 0.2.0-py36_1 conda-forge
lxml: 3.7.3-py36_0 --> 3.7.3-py36_0 conda-forge
mistune: 0.7.4-py36_0 --> 0.7.4-py36_0 conda-forge
mpmath: 0.19-py36_1 --> 0.19-py36_1 conda-forge
msgpack-python: 0.4.8-py36_0 --> 0.4.8-py36_0 conda-forge
multipledispatch: 0.4.9-py36_0 --> 0.4.9-py36_0 conda-forge
nbconvert: 5.1.1-py36_0 --> 5.1.1-py36_0 conda-forge
nbformat: 4.3.0-py36_0 --> 4.3.0-py36_0 conda-forge
networkx: 1.11-py36_0 --> 1.11-py36_0 conda-forge
notebook: 5.0.0-py36_0 --> 5.0.0-py36_0 conda-forge
numexpr: 2.6.2-np112py36_0 --> 2.6.2-np112py36_0 conda-forge
numpydoc: 0.6.0-py36_0 --> 0.6.0-py36_0 conda-forge
olefile: 0.44-py36_0 --> 0.44-py36_0 conda-forge
packaging: 16.8-py36_0 --> 16.8-py36_0 conda-forge
pandas: 0.20.1-np112py36_0 --> 0.20.1-np112py36_0 conda-forge
pandocfilters: 1.4.1-py36_0 --> 1.4.1-py36_0 conda-forge
partd: 0.3.8-py36_0 --> 0.3.8-py36_0 conda-forge
pathlib2: 2.2.1-py36_0 --> 2.2.1-py36_0 conda-forge
patsy: 0.4.1-py36_0 --> 0.4.1-py36_0 conda-forge
prompt_toolkit: 1.0.14-py36_0 --> 1.0.14-py36_0 conda-forge
py: 1.4.33-py36_0 --> 1.4.33-py36_0 conda-forge
pycparser: 2.17-py36_0 --> 2.17-py36_0 conda-forge
pyflakes: 1.5.0-py36_0 --> 1.5.0-py36_0 conda-forge
pygments: 2.2.0-py36_0 --> 2.2.0-py36_0 conda-forge
pylint: 1.6.4-py36_1 --> 1.6.4-py36_1 conda-forge
pyqt: 5.6.0-py36_2 --> 5.6.0-py36_2 conda-forge
pytest: 3.0.7-py36_0 --> 3.0.7-py36_0 conda-forge
python-dateutil: 2.6.0-py36_0 --> 2.6.0-py36_0 conda-forge
pytz: 2017.2-py36_0 --> 2017.2-py36_0 conda-forge
pywavelets: 0.5.2-np112py36_0 --> 0.5.2-np112py36_0 conda-forge
pyyaml: 3.12-py36_0 --> 3.12-py36_0 conda-forge
pyzmq: 16.0.2-py36_0 --> 16.0.2-py36_0 conda-forge
qtawesome: 0.4.4-py36_0 --> 0.4.4-py36_0 conda-forge
qtconsole: 4.3.0-py36_0 --> 4.3.0-py36_0 conda-forge
qtpy: 1.2.1-py36_0 --> 1.2.1-py36_0 conda-forge
scikit-image: 0.13.0-np112py36_0 --> 0.13.0-np112py36_0 conda-forge
seaborn: 0.7.1-py36_0 --> 0.7.1-py36_0 conda-forge
singledispatch: 3.4.0.3-py36_0 --> 3.4.0.3-py36_0 conda-forge
snowballstemmer: 1.2.1-py36_0 --> 1.2.1-py36_0 conda-forge
sphinx: 1.5.6-py36_0 --> 1.5.6-py36_0 conda-forge
spyder: 3.1.4-py36_0 --> 3.1.4-py36_0 conda-forge
statsmodels: 0.8.0-np112py36_0 --> 0.8.0-np112py36_0 conda-forge
sympy: 1.0-py36_0 --> 1.0-py36_0 conda-forge
tblib: 1.3.2-py36_0 --> 1.3.2-py36_0 conda-forge
testpath: 0.3-py36_0 --> 0.3-py36_0 conda-forge
toolz: 0.8.2-py36_0 --> 0.8.2-py36_0 conda-forge
tornado: 4.5.1-py36_0 --> 4.5.1-py36_0 conda-forge
traitlets: 4.3.2-py36_0 --> 4.3.2-py36_0 conda-forge
vs2015_runtime: 14.0.25123-0 --> 14.0.25123-0 conda-forge
wcwidth: 0.1.7-py36_0 --> 0.1.7-py36_0 conda-forge
werkzeug: 0.12.2-py36_0 --> 0.12.2-py36_0 conda-forge
wheel: 0.29.0-py36_0 --> 0.29.0-py36_0 conda-forge
widgetsnbextension: 2.0.0-py36_0 --> 2.0.0-py36_0 conda-forge
xlrd: 1.0.0-py36_0 --> 1.0.0-py36_0 conda-forge
xlsxwriter: 0.9.6-py36_0 --> 0.9.6-py36_0 conda-forge
zict: 0.1.2-py36_0 --> 0.1.2-py36_0 conda-forge
zlib: 1.2.8-vc14_3 [vc14] --> 1.2.8-vc14_3 conda-forge [vc14]
Proceed ([y]/n)? n