Can't install Python 3.5 files for Zipline

Question

I'm trying to install Zipline and all of its dependencies using conda for Python 3.5. However, I'm only getting the 2.7 versions of the files:

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

I can see that Python 3.5 files are available on Anaconda . How do I specify that I want the Python 3.5 files, not the 2.7 ones?

I ran the following commands from the Anaconda prompt:

conda create -n py35 python=3.5
conda activate py35
conda install -c Quantopian zipline

Answer 1

This happened to me as well. I quitted the zipline installation process and installed some other packages instead. Then I tried to install zipline again, and conda did not asked to downgrade python anymore. So I guess it is just some automatic environment solving mechanism with conda. You can try install zipline first, then upgrade python back to 3.5 again.