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pythonjson
Chris Snow
Chris Snow

Reputation: 24606

how can I parse json with a single line python command?

I would like to use python to parse JSON in batch scripts, for example:

HOSTNAME=$(curl -s "$HOST" | python ?)

Where the JSON output from curl looks like:

'{"hostname":"test","domainname":"example.com"}'

How can I do this with a single line python command?

Upvotes: 19

Views: 36864

Answers (4)

MonaPy
MonaPy

Reputation: 349

Run this:

$ python -m json.tool

It reads input from stdin and print out in a nicely. So with your questions:

HOSTNAME=$(curl -s "$HOST" | python -m json.tool )

Upvotes: 0

Chris Snow
Chris Snow

Reputation: 24606

Based on the JSON below being returned from the curl command ...

'{"hostname":"test","domainname":"example.com"}'

You can then use python to extract the hostname using the python json module:

HOSTNAME=$(curl -s "$HOST" |
  python -c \
    'import json,sys;print(json.load(sys.stdin)["hostname"])')

Note that I have split the line using a \ to make it more readable on stackoverflow. I've also simplified the command based on chepner's comment.

Original source: Parsing JSON with Unix tools

See also: https://wiki.python.org/moin/Powerful%20Python%20One-Liners

Upvotes: 23

Alejandro Galera
Alejandro Galera

Reputation: 3691

Since Python is multiplatform, is important to note differences between Linux and Windows, especially because of how they treat double-quotes/single-quotes differently.

Second, some previous answers are a little bit obsolete: in python2, print without parentheses was permitted. Nevertheless, in python3, print must be between parentheses.

Linux (bash)

It doesn't matter how you put double/single quotes. Json can be parsed in both ways with "keys" or 'keys'

HOSTNAME=$(curl -s "$HOST" |
  python3 -c 'import json,sys;print(json.load(sys.stdin)["hostname"])')

It also works: (pay attention at single/double quote at key)

HOSTNAME=$(curl -s "$HOST" |
  python3 -c "import json,sys;print(json.load(sys.stdin)['hostname'])")

Windows (powershell)

Keys in json MUST be between single quotes. Only the following syntax is accepted.
The ConvertTo-Json function generates object and works with keys between single quotes.

$HOSTNAME=(Invoke-RestMethod $HOST | `
  ConvertTo-Json | `
  python3 -c "import json,sys; print(json.load(sys.stdin)['hostname'])")

Upvotes: 6

hustljian
hustljian

Reputation: 1055

echo '{"hostname":"test","domainname":"example.com"}' | python -m json.tool

Upvotes: 16

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