Order list by string value

Hi, I need to order a list of items, by a string value...
e.g. 635, 955, 5820, 1010 should appear as 635,955,1010,5820, however it shows up as 1010, 5820, 635, 955 because it's a string and not an integer.
I cannot convert to integer, it must eb a string value. Any suggestions as to how this can be done simply using a string value?

...