15.list统计各个元素的个数

dc_array = {}
list_array = ['1', '2', '3', '2', '4', '2', '3', '5']
set_array = set(list_array)
for item in set_array:
    dc_array.update({item: list_array.count(item)})
print dc_array

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{'1': 1, '3': 2, '2': 3, '5': 1, '4': 1}