python - Remove the first character of a string

Your problem seems unclear. You say you want to remove "a character from a certain position" then go on to say you want to remove a particular character.

If you only need to remove the first character you would do:

s = ":dfa:sif:e"
fixed = s[1:]

If you want to remove a character at a particular position, you would do:

s = ":dfa:sif:e"
fixed = s[0:pos]+s[pos+1:]

If you need to remove a particular character, say ':', the first time it is encountered in a string then you would do:

s = ":dfa:sif:e"
fixed = ''.join(s.split(':', 1))