every time we want to extract last name or give raisewe'll have to repeat the kinds of code we just typedthat could become problem if we ever change the way those operations work--we may have to update many places in our code we'll address these issues in few moments field labels perhaps more fundamentallyaccessing fields by position in list requires us to memorize what each position meansif you see bit of code indexing record on magic position how can you tell it is extracting payin terms of understanding the codeit might be better to associate field name with field value we might try to associate names with relative positions by using the python range builtin functionwhich generates successive integers when used in iteration contexts (such as the sequence assignment used initially here)nameagepay range( bob ['bob smith' bob[name'bob smithpaybob[pay( and this addresses readabilitythe three uppercase variables essentially become field names this makes our code dependent on the field position assignmentsthough-we have to remember to update the range assignments whenever we change record structure because they are not directly associatedthe names and records may become out of sync over time and require maintenance step moreoverbecause the field names are independent variablesthere is no direct mapping from record list back to its field' names raw record listfor instanceprovides no way to label its values with field names in formatted display in the preceding recordwithout additional codethere is no path from value to label agebob index( gives the value of agebut not the name age itself we might also try this by using lists of tupleswhere the tuples record both field name and valuebetter yeta list of lists would allow for updates (tuples are immutablehere' what that idea translates towith slightly simpler recordsbob [['name''bob smith']['age' ]['pay' ]sue [['name''sue jones']['age' ]['pay' ]people [bobsuethis really doesn' fix the problemthoughbecause we still have to index by position in order to fetch fieldsfor person in peopleprint(person[ ][ ]person[ ][ ]namepay step representing records