[开发工具]python --统计列表中各元素出现的次数

统计列表中的字典

方法一:

a = [{'appreciation_id': 1341, 'level_name': 'S'}, {'appreciation_id': 1341, 'level_name': 'S'},
     {'appreciation_id': 1341, 'level_name': 'S'}, {'appreciation_id': 1342, 'level_name': 'A'},
     {'appreciation_id': 1342, 'level_name': 'A'}, {'appreciation_id': 1342, 'level_name': 'A'},
     {'appreciation_id': 1342, 'level_name': 'A'}, {'appreciation_id': 1343, 'level_name': 'B'},
     {'appreciation_id': 1344, 'level_name': 'C'}, {'appreciation_id': 1345, 'level_name': 'E'},
     {'appreciation_id': 1351, 'level_name': 'F'}]


from collections import Counter

res = Counter([i.get('level_name') for i in a if a])
print(res)

输出:
Counter({'A': 4, 'S': 3, 'B': 1, 'C': 1, 'E': 1, 'F': 1})

方法二：

a = [{'appreciation_id': 1341, 'level_name': 'S'}, {'appreciation_id': 1341, 'level_name': 'S'},
 {'appreciation_id': 1341, 'level_name': 'S'}, {'appreciation_id': 1342, 'level_name': 'A'},
 {'appreciation_id': 1342, 'level_name': 'A'}, {'appreciation_id': 1342, 'level_name': 'A'},
 {'appreciation_id': 1342, 'level_name': 'A'}, {'appreciation_id': 1343, 'level_name': 'B'},
 {'appreciation_id': 1344, 'level_name': 'C'}, {'appreciation_id': 1345, 'level_name': 'E'},
 {'appreciation_id': 1351, 'level_name': 'F'}]

result = {}
for i in a:
    if i.get('level_name') not in result:
        result[i.get('level_name')] = 1
    else:
        result[i.get('level_name')] += 1
print(result)

方法三:
a = [{'appreciation_id': 1341, 'level_name': 'S'}, {'appreciation_id': 1341, 'level_name': 'S'},
 {'appreciation_id': 1341, 'level_name': 'S'}, {'appreciation_id': 1342, 'level_name': 'A'},
 {'appreciation_id': 1342, 'level_name': 'A'}, {'appreciation_id': 1342, 'level_name': 'A'},
 {'appreciation_id': 1342, 'level_name': 'A'}, {'appreciation_id': 1343, 'level_name': 'B'},
 {'appreciation_id': 1344, 'level_name': 'C'}, {'appreciation_id': 1345, 'level_name': 'E'},
 {'appreciation_id': 1351, 'level_name': 'F'}]

result = {}
for i in a:
    result.setdefault(i.get('level_name'), 0)
    result[i.get('level_name')] += 1

print(result)

统计纯列表

方法一:

a = ['h', 'h', 'e', 'a', 'a']
result = {}
for i in a:
    result.setdefault(i, 0)
    result[i] += 1

print(result)

输出:
	{'h': 2, 'e': 1, 'a': 2}

方法二:
a = ['h','h','e','a','a']
result = {}
for i in a:
    if i not in result:
        result[i] = 1
    else:
        result[i] += 1
print(result)

输出:
	{'h': 2, 'e': 1, 'a': 2}

方法三:
	
num = [1, 1, 2, 2, 3, 4, 4, 1]
set_num = set(num)  # set()会创建一个无序且不重复的集合
for i in set_num:
    print('%d--数量：%d' % (i,num.count(i)))

方法四:

from collections import Counter
num = [1, 1, 2, 2, 3, 4, 4, 1]
new_num = Counter(num)
print(new_num)

方法五:

num = [1, 1, 2, 2, 3, 4, 4, 1]
dic_num = {}
for i in num:
    dic_num[i] = num.count(i)
for key,value in dic_num.items():
    print('%s--数量%d' % (key,value))