sed extracting group of digits

Question

I have tried to extract a number as given below but nothing is printed on screen:

echo \"This is an example: 65 apples\" | sed -n  \'s/.*\\([0-9]*\\) apples/\\1/         


        

Answer 1

A simple way for extracting all numbers from a string

echo "1213 test 456 test 789" | grep -P -o "\d+"

And the result:

1213
456
789