read text file two words at a time in a loop in bash

I have a text file with a space separated list of numbers (lat/lon) that looks like this :

-8.000 43.860 -9.000 43.420 -9.350 43.220 -9.388 42.893 -9.000 42.067 -8.935 41.308 -9.000 40.692 -9.278 40.000 -9.324 39.550 -9.518 39.387 -9.777 38.883 -9.285 38.378 -8.909 38.293 -8.951 38.000 -8.965 37.953 -8.917 37.833 -8.913 37.667 -8.915 37.500 -8.975 37.333 -9.017 37.167 -9.045 37.000

I know how to loop through the numbers one by one in bash like this

awk '{ for ( i = 1; i < NF; ++i ) print $(i); }' example.txt |
while IFS= read -r lon lat
do 
    echo processing: "$lon $lat" 
done

giving:

processing: -8.000 
processing: 43.860 
processing: -9.000 
processing: 43.420 
processing: -9.350 
processing: 43.220 

etc, but how can I loop through the file pair-wise?

i.e. something like (but this obviously doesn’t work):

while IFS= read -r lon lat
do 
    echo processing: "$lon $lat " 
done

to give me lon=-8, lat=43.86 on the first loop etc…?

>Solution :

You can read all the fields in a line into an array (with read -a), and then loop over that:

while read -r -a fields; do
    for ((i=0; i < ${#fields[@]}; i += 2)); do
        echo "${fields[i]}" "${fields[i+1]}"
    done
done < example.txt

-8.000 43.860
-9.000 43.420
-9.350 43.220
...