Question

我有一个排序列表，我想不使用count()函数来计算每个数字的出现次数。

sameItem = 0
startPosition = 1

sortedList  = [13, 15, 15, 17, 18, 18, 18, 18, 19, 20, 20, 20, 20, 21, 22, 22, 22, 22, 23, 23, 23, 24, 24, 26, 26, 26, 27, 27, 27, 28]

for i in range(1, len(sortedList)):

    item1 = sortedList[i - 1]
    item2 = sortedList[i]
    countItems = 1
    sameItem = countItems

    if item1 == item2:
        startPosition = i
        while (sortedList[i - 1] == sortedList[startPosition]):
           sameItem += 1
           startPosition += 1

    else:
        sameItem = countItems

    print(str(item1) + " appears " + str(sameItem) + " times")

Answer 1

您可以使用itertools.groupby：

from itertools import groupby
for k, g in groupby(sortedList):
    print('%s appears %d times' % (k, len(list(g))))

或者，如果您不想使用任何库函数：

count = 1
for i, n in enumerate(sortedList):
    if i == len(sortedList) - 1 or n != sortedList[i + 1]:
        print('%s appears %d times' % (n, count))
        count = 1
    else:
        count += 1

或者，如果您根本不想使用任何功能（实际上print也是一个功能，但我认为您不能不使用它）

last = None
for n in sortedList:
    if n != last:
        if last is not None:
            print('%s appears %d times' % (last, count))
        last = n
        count = 1
    else:
        count += 1
print('%s appears %d times' % (last, count))

以上所有输出：

13 appears 1 times
15 appears 2 times
17 appears 1 times
18 appears 4 times
19 appears 1 times
20 appears 4 times
21 appears 1 times
22 appears 4 times
23 appears 3 times
24 appears 2 times
26 appears 3 times
27 appears 3 times
28 appears 1 times

Answer 2

i = 1

check = False

sameItem = 0

while（i

if sortedList[i-1] == sortedList[i]:
    check = True
    j = i

    while (sortedList[i-1] == sortedList[j]) and (check == True):
        sameItem += 1
        j += 1

        if (sortedList[i-1] != sortedList[j]):
            check = False
        i = j

    print(str(sortedList[i-1]) + " appears " + str(sameItem) + " times")

else:
    sameItem = 1
    print(str(sortedList[i-1]) + " appears " + str(sameItem) + " times")

i += 1

我有一个排序列表，我想在不使用count（）函数的情况下计算每个数字的出现次数

2 个答案: