How to simultaneously access two arrays indexes for a curl request in Bash for loop?

Question

In Bash i am trying to query country currencies from http://free.currencyconverterapi.com/api/v5/convert?q=USD_GBP and update my OpenEdge API automatically without Hard coding the symbols. meaning I have to curl and save currency symbols from my API in an array and curl and save the values from the currency converter API. after that i want to run two for loops simultaneously or access the indexes of two arrays at the same time in order to run the API call that requires the

url/rest/USD/12

kind of input.

In bash I am calling a curl that returns

ZAR USD EUR BWP CHF GBP  

from my API in one line. Then i save that result in a variable called currency

jsonEnd="_ZAR.val"
symbolEnd="_ZAR"

I then run

values=()
for j in ${currency[*]};
do
        ${values[j]}=$(curl -X GET -H "Content-type: application/json" http://free.currencyconverterapi.com/api/v5/convert?q=${currency[j]}$symbolEnd&compact=y | jq '.${currency[j]}$jsonEnd')         
done

To get the currency values into an array where '_ZAR.val' is a from a json result, tried to point at "val" with jq

{
"USD_ZAR": {
    "val": 14.23065
} }

at last i am trying to run a POST Curl which needs the relative currency symbol found above like USD with a value to update. in this form

curl -X PUT -H "Content-Type: application/json" -H "Authorization: $context" http://192.168.xxx.xxx:8080/rest/exchangerates/USD/12

i tried this

for i in ${values[@]}
do    
      curl -X PUT -H "Content-Type: application/json" -H "Authorization: $context" http://192.168.xxx.xxx:8080/rest/exchangerates/${currency[i]}/${values[i]}
done

i can't get it right, the errors include

curl: (6) Could not resolve host: USD_ZAR

etc I am new to bash

Answer 1

Both ${currency[*]} and ${currency[*]} will expand to the values inside the array. So when you write ...

for j in "${currency[@]}"; do
    echo "${currency[j]}"         
done

... you do not access something like ${currency[0]} but ${currency[USD]} which does not exist.

Also, to assign variables you cannot write ${array[i]}=value but have to use array[$i]=value .

You may also want to switch to an associative array (also known as dictionary or map ) where you can use strings as indices. Here is a rough skeleton:

currencies=(ZAR USD EUR BWP CHF GBP)
declare -A values
for c in "${currencies[@]}"; do
    values["$c"]="$(curl ..."$c"... | jq ..."$c"... )"
done

c=EUR
echo "The value of $c is ${values[$c]}"