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jsonbashdecimaljqnumber-formatting

jq reformatting decimals in scientific notation -- can this be avoided?


I found difference between json-data created by JavaScipt and via jq with bash (and other programming languages). With JavaScript I can create decimal numbers with up to six digits after the point, even when I use float(). But with jq its different, because adding a decimal value takes four digits after the decimal point only.

My problem is that I need decimal numbers to store in SQL, with up to six digits after the point.

Example:

$ JSON='{"decimal":0.00001}'
$ echo "$JSON" | jq .
{
  "decimal": 1e-05
}

My goal is to validate the decimal with this line ...

if [[ "$TMP_DECIMAL" =~ ^[0-9]+([.][0-9]+)?$ ]] ; then

Any tip / suggsestion ?


Solution

  • You can't change jq's behavior -- at present date, relevant feature requests are still open -- but you can reformat your numbers after they've been retrieved. For example:

    json='{"decimal":0.00001}'
    decimal=$(jq '.decimal' <<<"$json")
    decimal_f=$(awk -v decimal="$decimal" 'BEGIN { printf("%f\n", decimal) }' </dev/null)
    
    echo "JQ emitted $decimal; reformatted as $decimal_f"