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python 统计数组中元素出现次数并进行排序的实例

更新时间:2020-06-08 18:24:01 作者:startmvc
如下所示:lis=[12,34,456,12,34,66,223,12,5,66,12,23,66,12,66,5,456,12,66,34,5,34]deftest1():#进行去重c=[]foriin

如下所示:


lis = [12,34,456,12,34,66,223,12,5,66,12,23,66,12,66,5,456,12,66,34,5,34]

def test1():
 #进行去重
 c = []
 for i in lis:
 if i not in c:
 c.append(i)
 #进行统计,生成二维列表
 b = []
 for i in c:
 num = 0
 for j in range(len(lis)):
 if lis[j] == i:
 num += 1
 a = []
 a.append(i)
 a.append(num)
 b.append(a)
 # 排序算法,按出现次数进行降序排列
 for i in range(len(b)):
 for j in range(i,len(b)):
 if b[i][1] < b[j][1]:
 temp = b[i]
 b[i] = b[j]
 b[j] = temp
 print(b)

def test2():
 # set进行去重,进行统计生成二维列表
 b = []
 for i in list(set(lis)):
 num = 0
 for j in range(len(lis)):
 if lis[j] == i:
 num += 1
 a = []
 a.append(i)
 a.append(num)
 b.append(a)
 # 排序算法,按出现次数进行降序排列
 for i in range(len(b)):
 for j in range(i,len(b)):
 if b[i][1] < b[j][1]:
 temp = b[i]
 b[i] = b[j]
 b[j] = temp
 print(b)

def test3():
 # 统计元素出现次数,元素为key,次数为value,生成字典
 a = {}
 for i in lis:
 if i in a:
 a[i] = a[i] + 1
 else:
 a[i] = 1
 # 使用sorted对字典进行排序
 b = sorted(a.items(),key=lambda item:item[1],reverse=True)
 print(b)

def test4():
 from collections import Counter
 import operator
 #进行统计
 a = dict(Counter(lis))
 #进行排序
 b= sorted(a.items(), key=operator.itemgetter(1),reverse=True)
 print(b)

if __name__ == '__main__':
 test1()
 test2()
 test3()
 test4()

输出结果如下:


[[12, 6], [66, 5], [34, 4], [5, 3], [456, 2], [223, 1], [23, 1]]
[[12, 6], [66, 5], [34, 4], [5, 3], [456, 2], [23, 1], [223, 1]]
[(12, 6), (66, 5), (34, 4), (5, 3), (456, 2), (23, 1), (223, 1)]
[(12, 6), (66, 5), (34, 4), (5, 3), (456, 2), (23, 1), (223, 1)]

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python 统计数组 次数