You can use a lambda
that sorts your data based on the number in the second column.
with open('csvfile1.csv') as input:
reader = csv.reader(input, delimiter = " ")
sortedlist = sorted(reader, key=lambda col: int(col[1]), reverse=False)
print(", ".join([lst[0] for lst in sortedlist]))
# city3, city4, city5, city1, city2
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