python - 日期比较/连续日期分组

Question

我正在尝试编写一个函数来识别日期组并测量该组的大小。

该函数将获取已按日期顺序排序的元素列表(这些元素是包含日期的 CSV 文件中的单独行)。该列表的长度可能是 0 到 n 个元素。我希望按照输入的方式编写列表，并添加日期组的大小。

例如列表

Bill 01/01/2011

Bill 02/01/2011

Bill 03/01/2011

Bill 05/01/2011

Bill 07/01/2011

应输出(最好打印到文件中)为

Bill 01/01/2011 3

Bill 02/01/2011  3

Bill 03/01/2011  3

Bill 05/01/2011  1

Bill 07/01/2011  1.

我已经有一个名为 isBeside(string1, string2) 的函数，它返回两者之间的增量。

到目前为止我的尝试是这样的(迭代困惑，我确信 python 可以比这更优雅)

注意 coll[i][1] 包含 CSV 行的日期元素。

def printSet(coll):
    setSize = len(coll)
    if setSize == 0:
    #dont need to do anything
elif setSize == 1:

    for i in coll:
        print i, 1

elif setSize > 1:

    printBuffer = [] ##new buffer list which will hold sequential dates, 
                        until a non-sequential one is found
    printBuffer.append(coll[0]) #add the first item
    print 'Adding ' + str(coll[0])

    for i in range(0, len(coll)-1):

        print 'Comparing ', coll[i][1], coll[i+1][1], isBeside(coll[i][1],  coll[i+1][1])

        if isBeside(coll[i][1],  coll[i+1][1]) == 1:
            printBuffer.append(coll[i+1])
            print 'Adding ' + str(coll[i+1])
        else:
            for j in printBuffer:
                print j, len(printBuffer)
            printBuffer = []
            printBuffer.append(coll[i])

return

Answer 1

类似这样的吗？

from datetime import date, timedelta

coll = [['Bill', date(2011,1,1)],
        ['Bill', date(2011,1,2)],
        ['Bill', date(2011,1,3)],
        ['Bill', date(2011,1,5)],
        ['Bill', date(2011,1,7)]]

res = []
group = [coll[0]]
i = 1

while i < len(coll):
    row = coll[i]
    last_in_group = group[-1]

    # use your isBeside() function here...
    if row[1] - last_in_group[1] == timedelta(days=1):
        # consecutive, append to current group..
        group.append(row)
    else:
        # not consecutive, start new group.
        res.append(group)
        group = [row]
    i += 1

res.append(group)

for group in res:
    for row in group:
        for item in row:
            print item,
        print len(group)

它打印:

Bill 2011-01-01 3
Bill 2011-01-02 3
Bill 2011-01-03 3
Bill 2011-01-05 1
Bill 2011-01-07 1