我正在尝试使用conda为Python 3.5安装Zipline及其所有依赖项。但是，我只获得2.7版本的文件：
The following packages will be downloaded:
package | build
---------------------------|-----------------
logbook-0.12.5 | py27_0 111 KB quantopian
zipline-0.7.0 | np18py27_0 241 KB quantopian
ta-lib-0.4.8 | np18py27_0 6.3 MB quantopian
------------------------------------------------------------
Total: 6.7 MB
The following NEW packages will be INSTALLED:
asn1crypto: 0.24.0-py27_0
backports: 1.0-py27_1
backports.functools_lru_cache: 1.5-py27_1
backports_abc: 0.5-py27h6d9a788_0
ca-certificates: 2018.12.5-0
cffi: 1.11.5-py27hc64555f_1
chardet: 3.0.4-py27_1
cryptography: 2.4.2-py27hc64555f_0
cycler: 0.10.0-py27h0308610_0
dateutil: 2.4.1-py27_0
enum34: 1.1.6-py27_1
freetype: 2.9.1-h4d385ea_1
functools32: 3.2.3.2-py27_1
futures: 3.2.0-py27_0
icu: 58.2-hb13015a_1
idna: 2.8-py27_0
ipaddress: 1.0.22-py27_0
jpeg: 9b-hb117b5b_2
kiwisolver: 1.0.1-py27hc56fc5f_0
libpng: 1.6.36-h7a46e7a_0
logbook: 0.12.5-py27_0 quantopian
matplotlib: 2.2.3-py27h263d877_0
numpy: 1.8.2-py27_0
openssl: 1.0.2p-h0c8e037_0
pandas: 0.14.1-np18py27_0
pycparser: 2.19-py27_0
pyopenssl: 18.0.0-py27_0
pyparsing: 2.3.1-py27_0
pyqt: 5.6.0-py27hc56fc5f_6
pysocks: 1.6.8-py27_0
python-dateutil: 2.7.5-py27_0
pytz: 2018.9-py27_0
qt: 5.6.2-vc9he136c73_12
requests: 2.21.0-py27_0
scipy: 0.14.0-np18py27_0
singledispatch: 3.4.0.3-py27h18657b7_0
sip: 4.18.1-py27hc56fc5f_2
six: 1.12.0-py27_0
sqlite: 3.26.0-h0c8e037_0
ta-lib: 0.4.8-np18py27_0 quantopian
tornado: 5.1.1-py27h0c8e037_0
urllib3: 1.24.1-py27_0
vs2008_runtime: 9.00.30729.1-hfaea7d5_1
win_inet_pton: 1.0.1-py27_1
zipline: 0.7.0-np18py27_0 quantopian
zlib: 1.2.11-h3cc03e0_3
The following packages will be UPDATED:
certifi: 2018.8.24-py35_1 --> 2018.11.29-py27_0
pip: 10.0.1-py35_0 --> 18.1-py27_0
setuptools: 40.2.0-py35_0 --> 40.6.3-py27_0
wheel: 0.31.1-py35_0 --> 0.32.3-py27_0
wincertstore: 0.2-py35h3d52121_0 --> 0.2-py27h87a2792_0
The following packages will be DOWNGRADED:
python: 3.5.6-he025d50_0 --> 2.7.15-hcb6e200_5
vc: 14.1-h0510ff6_4 --> 9-h7299396_1
Proceed ([y]/n)? n
我可以看到Python 3.5文件是available on Anaconda。如何指定我想要Python 3.5文件，而不是2.7文件？
我从Anaconda提示符运行以下命令：
conda create -n py35 python=3.5
conda activate py35
conda install -c Quantopian zipline
这也发生在我身上。我退出了zipline安装过程并安装了一些其他软件包。然后我再次尝试安装zipline，conda没有要求降级python。所以我猜这只是conda的一些自动环境解决机制。您可以先尝试安装zipline，然后再将python升级回3.5。