List 자료형의 Join함수 사용하기

Question:
	Write a program which will find all such numbers which are divisible by 7 but are not a multiple of 5,
	between 2000 and 3200 (both included).
	The numbers obtained should be printed in a comma-separated sequence on a single line.

def divisibleSevenNotDivisibleFive():

listOfNumber = ""

# Range: 2000 ~ 3200

for i in range(2000, 3201):

if((i % 7 == 0) and (i % 5 != 0)):

listOfNumber = listOfNumber + str(i) + ", "

return listOfNumber

print (divisibleSevenNotDivisibleFive())

위와 같이 프로그래밍을 하게되면 마지막 3199, 하고 comma를 찍게된다.

if문에 해당되면 그 숫자와 함께 comma를 문자열에 덮어씌우니까 말이다.

그러나 아래와 같이 join 함수를 이용하면 해결할 수 있다.

def divisibleSevenNotDivisibleFive():

# Convert data type from string to list

listOfNumber = []

# Range: 2000 ~ 3200

for i in range(2000, 3201):

if((i % 7 == 0) and (i % 5 != 0)):

# Append data by list's built-in "append" function

listOfNumber.append(str(i))

return listOfNumber

print (", ".join(divisibleSevenNotDivisibleFive()))

Reference site : 

https://github.com/zhiwehu/Python-programming-exercises/blob/master/100%2B%20Python%20challenging%20programming%20exercises.txt