Extracting only numbers from a column

[justinx]

Let's say I have a column with data:

rat
35
5
yard
dog
4
cat
20
3
59

I want to have a column that extracts only the numbers to make:

35

5

20

3

59

How can I do this?

Edit: Never mind, found a way thank you

[Metoo7]

Please try this formula:
=IFERROR(INDEX($A$1:$A$10,SMALL(IF(ISNUMBER($A$1:$A$10),ROW($1:$10)),ROW(A1))),"")

if you are using Office 365, the formula is very simple
=FILTER(A1:$A$10,ISNUMBER($A$1:$A$10))