有时我们要安装特定版本特定编译的包，比如用conda search caffe搜索出以下内容：
caffe 1.0.0rc3 np111py27_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
1.0.0rc3 np111py27_nomkl_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free [nomkl]
1.0.0rc3 np111py34_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
1.0.0rc3 np111py34_nomkl_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free [nomkl]
1.0.0rc3 np111py35_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
1.0.0rc3 np111py35_nomkl_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free [nomkl]
1.0.0rc5 np112py27_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
1.0.0rc5 np112py27_nomkl_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free [nomkl]
1.0.0rc5 np112py35_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
1.0.0rc5 np112py35_nomkl_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free [nomkl]
1.0.0rc5 np112py36_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
1.0.0rc5 np112py36_nomkl_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free [nomkl]
1.0.0rc4 py27_blas_openblas_202 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge [blas_openblas]
1.0.0rc4 py27_blas_openblas_203 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge [blas_openblas]
1.0 py27_blas_openblas_200 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge [blas_openblas]
1.0 py27_blas_openblas_201 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge [blas_openblas]
1.0 py27_blas_openblas_202 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge [blas_openblas]
caffe-gpu 1.0.0rc5 np112py27_3 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
1.0.0rc5 np112py27_nomkl_3 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free [nomkl]
1.0.0rc5 np112py35_3 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
1.0.0rc5 np112py35_nomkl_3 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free [nomkl]
1.0.0rc5 np112py36_3 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
1.0.0rc5 np112py36_nomkl_3 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free [nomkl]
onnx-caffe2 0.2.1 py27_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge
0.2.1 py35_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge
0.2.1 py36_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge
1.0.0 py27_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge
1.0.0 py35_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge
1.0.0 py36_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge
我们想要安装caffe 版本号为1.0，build编号为py27_blas_openblas_201的包，但是用conda install caffe=1.0安装的却是py27_blas_openblas_200的包，这时候只限定版本号就不行了，这时我们可以用：