python运行shell指令传参数,将Ipython变量作为字符串参数传递给Shell命令

矫情吗；* 2022-10-04 12:53 165阅读 0赞

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How do I execute a shell command from Ipython/Jupyter notebook passing the value of a python string variable as a string in the bash argument like in this example:

sp\_name = 'littleGuy' \#the variable

sp\_details = !az ad app list --filter "DisplayName eq '$sp\_name'" \#the shell command

I've tried using $sp\_name alone, $\{sp\_name\}, \{sp\_name\} etc as outlined in this related question, but none have worked.

The kicker here is the variable name needs to be quoted as a string in the shell command.

EDIT1:

@manu190466. I was judging from the string output that your solution worked. It appears for some reason it does not in practice. I wonder if az ad app list URL encodes the query or something...?

Thoughts?

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解决方案

The main problem you encounters seems to come from the quotes needed in your string.

You can keep the quotes in your string by using a format instruction and a raw string.

Use a 'r' before the whole string to indicate it is to be read as raw string, ie: special caracters have to not be interpreted. A raw string is not strictly required in your case because the string constructor of python is able to keep single quotes in a double quotes declaration but I think it's a good habit to use raw string declarators when there are non alphanumerics in it.

There are at least two way to format strings :

Older method herited from ancient langages with % symbols:

sp\_name = 'littleGuy' \#the variable

sp\_query = r"DisplayName eq '%s'"%(sp\_name)

sp\_details = !az ad app list --filter \{sp\_query\}

Newer method with \{\} symbols and the format() method :

sp\_name = 'littleGuy' \#the variable

sp\_query = r"DisplayName eq '\{\}'".format(sp\_name)

sp\_details = !az ad app list --filter \{sp\_query\}

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[DOfmx.png]: https://i.stack.imgur.com/DOfmx.png