split 使用

split作用：把字符串变成列表，这个字符串必须是多行文字。如果是单行文字或一个单词是不行的，实例操作如下：

In [46]: output=subprocess.check_output(['df','-h'])
In [60]: print(output)
b'Filesystem               Size  Used Avail Use% Mounted on\n/dev/mapper/centos-root   48G  7.6G   40G  16% /\ndevtmpfs                 1.9G     0  1.9G   0% /dev\ntmpfs                    1.9G     0  1.9G   0% /dev/shm\ntmpfs                    1.9G   20M  1.9G   2% /run\ntmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup\n/dev/sda1               1014M  142M  873M  14% /boot\n/dev/mapper/centos-home   23G   40M   23G   1% /home\ntmpfs                    1.9G   12K  1.9G   1% /var/lib/kubelet/pods/5cdc5bde-23a2-11e9-8321-000c2935f634/volumes/kubernetes.io~secret/flannel-token-smd42\noverlay                   48G  7.6G   40G  16% /var/lib/docker/overlay/5e0d6edc162c3d5e1465e8cb69426423f27b74acbf2cb984fc012acbe0f804f0/merged\nshm                       64M     0   64M   0% /var/lib/docker/containers/9c450ecf4d7b750fef3a00f92a7a9a2c536df52041e04546c2350566f1e90206/shm\noverlay                   48G  7.6G   40G  16% /var/lib/docker/overlay/1932a1a32f66d39708a632c5e2b767ae5024484350ff7aa6072f46ad65393e1f/merged\ntmpfs                    378M     0  378M   0% /run/user/0\n'

In [56]: lines=output.decode('utf8').split('\n')
In [57]: lines
Out[57]:
['Filesystem               Size  Used Avail Use% Mounted on',
 '/dev/mapper/centos-root   48G  7.6G   40G  16% /',
 'devtmpfs                 1.9G     0  1.9G   0% /dev',
 'tmpfs                    1.9G     0  1.9G   0% /dev/shm',
 'tmpfs                    1.9G   20M  1.9G   2% /run',
 'tmpfs                    1.9G     0  1.9G   0% /sys/fs/cgroup',
 '/dev/sda1               1014M  142M  873M  14% /boot',
 '/dev/mapper/centos-home   23G   40M   23G   1% /home',
 'tmpfs                    1.9G   12K  1.9G   1% /var/lib/kubelet/pods/5cdc5bde-23a2-11e9-8321-000c2935f634/volumes/kubernetes.io~secret/flannel-token-smd42',
 'overlay                   48G  7.6G   40G  16% /var/lib/docker/overlay/5e0d6edc162c3d5e1465e8cb69426423f27b74acbf2cb984fc012acbe0f804f0/merged',
 'shm                       64M     0   64M   0% /var/lib/docker/containers/9c450ecf4d7b750fef3a00f92a7a9a2c536df52041e04546c2350566f1e90206/shm',
 'overlay                   48G  7.6G   40G  16% /var/lib/docker/overlay/1932a1a32f66d39708a632c5e2b767ae5024484350ff7aa6072f46ad65393e1f/merged',
 'tmpfs                    378M     0  378M   0% /run/user/0',
 '']
In [58]: for line in lines[1:-1]:
    ...:     if line:
    ...:         print(line.split()[-2])
    ...:
16%%%
2%%
14%
1%
1%
16%%
16%%