adding leading zero based on string length

[LarsFolkestad]

Dear all
I want to add a leading zero based on string length:

clear
input str10 var
"abcd"
"abc" 
"bcd" 
end

I do:

replace var="0"+var if strlen(var==3)

This gives me a type mismatch.

Im guessing I am missing something very simple.

Thank you
Lars

[Andrew Musau]

replace var="0"+var if strlen(var)==3

[LarsFolkestad]

Outside the parentheses...thx!