RLE compression/decompression

def RLEcompression(string):
#@param:
#   string: str;
#   return: str;
    newString = ""
    count = 1
    for i in range(0,len(string)):
        if i+1<len(string):
            if string[i]==string[i+1]:
                count += 1
            else:
                if count <=2:
                    newString = newString + count*string[i]
                else:
                    newString = newString + str(count) + string[i]
                count = 1
        else:
            if count <=2:
                newString = newString + count*string[i]
            else:
                newString = newString + str(count) + string[i]
                count = 1
    return newString
#-------------------------------------------------------------------------------
def RLEdecompression(string):
#@param:
#   string: str, RLE compressed string;
#   return: str;
    newString = ""
    for i in range(0,len(string)):
            if string[i].isdigit() and i+1<len(string):
                newString = newString + int(string[i])*string[i+1]
            else:
                newString = newString + string[i]
    return newString