一個數據幀可以在過濾的dict
values
dict comprehension
,然後DataFrame
完美的作品:
print ({k:v[:min_length] for k,v in data_dict.items()})
{'b': [1, 2, 3], 'c': [2, 45, 67], 'a': [1, 2, 3]}
df = pd.DataFrame({k:v[:min_length] for k,v in data_dict.items()})
print (df)
a b c
0 1 1 2
1 2 2 45
2 3 3 67
如果有可能一些長度可少爲min_length
添加Series
:
data_dict = {'a': [1,2,3,4], 'b': [1,2], 'c': [2,45,67,93,82,92]}
min_length = 3
df = pd.DataFrame({k:pd.Series(v[:min_length]) for k,v in data_dict.items()})
print (df)
a b c
0 1 1.0 2
1 2 2.0 45
2 3 NaN 67
時序:
In [355]: %timeit (pd.DataFrame({k:v[:min_length] for k,v in data_dict.items()}))
The slowest run took 5.32 times longer than the fastest. This could mean that an intermediate result is being cached.
1000 loops, best of 3: 520 µs per loop
In [356]: %timeit (pd.DataFrame({k:pd.Series(v[:min_length]) for k,v in data_dict.items()}))
The slowest run took 4.50 times longer than the fastest. This could mean that an intermediate result is being cached.
1000 loops, best of 3: 937 µs per loop
#Allen's solution
In [357]: %timeit (pd.DataFrame.from_dict(data_dict,orient='index').T.dropna())
1 loop, best of 3: 16.7 s per loop
代碼定時:
np.random.seed(123)
L = list('ABCDEFGH')
N = 500000
min_length = 10000
data_dict = {k:np.random.randint(10, size=np.random.randint(N)) for k in L}
我對這個解決方案有點熟悉。我想知道,有沒有其他有效的方法來做到這一點(而不是迭代所有的鍵)? –
但是我在你的結果中注意到的最奇怪的事情之一。 「最慢的跑步比最快的跑了5.32倍。這可能意味着中間結果正在被緩存。「熊貓緩存結果嗎? –
難題,我真的不知道答案。也許最好的創建新的問題或在stackoverflow找到答案。 – jezrael