目前,我正在处理不同主题的每周数据,但可能会有一些漫长的条纹而没有数据,因此,我想做的就是保持每id
个连续几周的最长条纹。我的数据如下:
id week
1 8
1 15
1 60
1 61
1 62
2 10
2 11
2 12
2 13
2 25
2 26
我的预期输出是:
id week
1 60
1 61
1 62
2 10
2 11
2 12
2 13
我有点接近,尝试在week
== week.shift()+1
时标记为1。问题在于这种方法不会标记连续出现的第一个事件,而且我也不能过滤最长的一次:
df.loc[ (df['id'] == df['id'].shift())&(df['week'] == df['week'].shift()+1),'streak']=1
根据我的示例,这将带来以下结果:
id week streak
1 8 nan
1 15 nan
1 60 nan
1 61 1
1 62 1
2 10 nan
2 11 1
2 12 1
2 13 1
2 25 nan
2 26 1
关于如何实现我想要的任何想法?
答案 0 :(得分:4)
尝试一下:
df['consec'] = df.groupby(['id',df['week'].diff(-1).ne(-1).shift().bfill().cumsum()]).transform('count')
df[df.groupby('id')['consec'].transform('max') == df.consec]
输出:
id week consec
2 1 60 3
3 1 61 3
4 1 62 3
5 2 10 4
6 2 11 4
7 2 12 4
8 2 13 4
答案 1 :(得分:1)
不如@ScottBoston简洁,但我喜欢这种方法
def max_streak(s):
a = s.values # Let's deal with an array
# I need to know where the differences are not `1`.
# Also, because I plan to use `diff` again, I'll wrap
# the boolean array with `True` to make things cleaner
b = np.concatenate([[True], np.diff(a) != 1, [True]])
# Tell the locations of the breaks in streak
c = np.flatnonzero(b)
# `diff` again tells me the length of the streaks
d = np.diff(c)
# `argmax` will tell me the location of the largest streak
e = d.argmax()
return c[e], d[e]
def make_thing(df):
start, length = max_streak(df.week)
return df.iloc[start:start + length].assign(consec=length)
pd.concat([
make_thing(g) for _, g in df.groupby('id')
])
id week consec
2 1 60 3
3 1 61 3
4 1 62 3
5 2 10 4
6 2 11 4
7 2 12 4
8 2 13 4