Question 108858 in Json Question posted in
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JSON, jq, merged text + variable + bash variable, arguments

I have similar file/data:

$ echo "[{"my_var1":"valueA", "my_var2": "valueB"}]"
{"my_var1":"valueA", "my_var2": "valueB"}]

in my code I need to get value of "my_var2", easy:

$ echo "[{"my_var1":"valueA", "my_var2": "valueB"}]" | 
jq -r '.[] .my_var2'

# correct result:
valueB

… but … I need to use bash variable to specify which variable I would like to get:

I can’t specify "my_var2", I have to use only "var2"

$ PART="var2"
$ echo "[{"my_var1":"valueA", "my_var2": "valueB"}]" | 
jq -r --arg JSONPART ${PART} '.[] .my_[$JSONPART]'

expected result:

valueB
Tags:

2

Answers


  1. 0

    This should work:

    $ PART="var2"
$ echo "[{"my_var1":"valueA", "my_var2": "valueB"}]" | 
jq -r ".[] .my_$PART"
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  2. 0

    The jq filter .xyz can be rewritten as .["xyz"]. Thus:

    $ PART='var2'
$ echo '[{"my_var1":"valueA", "my_var2": "valueB"}]' | 
jq -r --arg JSONPART "$PART" '.[]["my_" + $JSONPART]'
valueB

    (Don’t forget to properly quote your shell parameters when expanding!)

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