Jupyter/IPython SList:：从shell执行操作符“”获取未经标记的输出

Question

在Jupyter Notebook Python Cell中运行shell命令时，如下所示：

output = ! some-shell-command

发射到标准输出（stdout）的每一行都被捕获到一个类似于IPython的SList数据结构中。例如：

output = !echo -e 'line1\nline2\nline3'
print(output) # A IPython SList data-structure.

['line1', 'line2', 'line3']

但是，有时您希望保留原始字符串输出格式，而不将其标记到列表中，如下所示：

print(output)

line1
line2
line3

示例：对于结构化JSON输出（一个包含许多换行符的字符串），您不希望出现这种标记化

那么，如何使用!操作符在Jupyter Notebooks中执行shell命令，并检索未标记化的输出（如上所述）

理想情况下，解决方案应该是Jupyter Notebooks中的本地解决方案

谢谢大家!

Answer 1

对于这里希望将类型为SList的jupyter标准输出（stdout）转换为JSON的人，我就是这么做的：

import json
output = !command  #output is an SList
j_out = json.dumps(output)  #jout is a str
out_dict = json.loads(j_out) #out_dict is a list 
out_dict[i][j]... #to access list elements

这假设command已将要处理到python字典中的输出适当格式化

Answer 2

SList有许多属性，它们以各种形式返回它：

https://gist.github.com/parente/b6ee0efe141822dfa18b6feeda0a45e5

In [151]: ret = !ls *.json                                                                       
In [152]: ret                                                                                    
Out[152]: ['foo1.json', 'foo.json', 'logins.json', 'stack56532806.json']

作为列表

In [153]: ret.l                                                                                  
Out[153]: ['foo1.json', 'foo.json', 'logins.json', 'stack56532806.json']

作为换行符分隔字符串：

In [154]: ret.n                                                                                  
Out[154]: 'foo1.json\nfoo.json\nlogins.json\nstack56532806.json'

以空格分隔：

In [155]: ret.s                                                                                  
Out[155]: 'foo1.json foo.json logins.json stack56532806.json'
In [156]: type(ret)                                                             

它的文件

In [158]: ret?                                                                                   
Type:        SList
String form: ['foo1.json', 'foo.json', 'logins.json', 'stack56532806.json']
Length:      4
File:        /usr/local/lib/python3.6/dist-packages/IPython/utils/text.py
Docstring:  
List derivative with a special access attributes.

These are normal lists, but with the special attributes:

* .l (or .list) : value as list (the list itself).
* .n (or .nlstr): value as a string, joined on newlines.
* .s (or .spstr): value as a string, joined on spaces.
* .p (or .paths): list of path objects (requires path.py package)

Any values which require transformations are computed only once and
cached.

Answer 3

使用join()将迭代器组合成字符串

"\n".join(output)