I believe that the reason for putting the 'k' between digits instead of the decimal point is to reduce errors as a decimal point is easy to mis-print or dissapear in subsequent copies/documents.
There is also two main types of colour coding for resistors, 4 band and 5 band.
4k7 in 4 band would be yellow,violet, red, with the fourth band indicating tolerance...i.e. gold is 5%, red is 2% and brown is 1%
4k7 in 5 band would be yellow, violet, brown, black, with the fifth bieng the tolerance.
47k on the other hand is yellow, violet, orange plus tolerance (4 band) or
yellow, violet, black, red plus tolerance (5 band).