我在这里很新。我有一个像这样的pandas数据框:
078401115X 0790747324 0790750708
A10ODC971MDHV8 0 0 [(354, 1), (393, 1)]
A16CZRQL23NOIW 0 [(124, 1), (697, 1)] 0
A19ZXK9HHVRV1X 0 0 0
我的索引列为零(第一行):
['078401115X',
'0790747324']
现在,我正在尝试在pandas数据帧的那些位置存储numpy零的数组,无论如何直接这样做没有'for循环'我设法用标量值但是我不能这样做与numpy数组。
非常感谢你的帮助。
答案 0 :(得分:0)
df.loc[list_indices, column_name] = np.zeros(4)
是你想要的。 df
是您的数据框,list_indices
是行为0的索引列表,np.zeros
列出零。如果你想要不同的课程长度,请更改4。
df.loc[list_indices, column_name]
选择索引位于list_indices
且列位为column_name
的行。
答案 1 :(得分:0)
.loc
和DataFrame
尺寸匹配以下是使用.loc
零索引的完整解决方案,并克服了您的维度/长度错误
error: 'cannot set using a list-like indexer with a different length than the value'
要匹配尺寸,请在分配给零索引而不是分配原始数组时,以所需/需要的形状创建一个DataFrame
个零数组。
import numpy as np
import pandas as pd
from cStringIO import StringIO
# Create example DataFrame
df_text = '''
078401115X| 0
0790747324| 0
0790750708|[(354, 1), (393, 1), (447, 1), (642, 1), (886,1)]
0800103688| 0
5556167281|[(41, 1), (86, 1), (341, 1), (362, 1), (419, 10)]
6300157423| 0
6300266850| 0
6301699599| 0
6301723465| 0
'''
df = pd.read_table(StringIO(df_text), sep='|', index_col=0, header=None, skipinitialspace=True)
print 'Original DataFrame:'
print df
print
# Find indexes with zero data in first column
zero_indexes = df[df[1] == '0'].index
print 'Zero Indexes:'
print zero_indexes.tolist()
print
# Assign numpy zero array to indexes
df.loc[zero_indexes] = pd.DataFrame([[np.zeros(4)]], index=zero_indexes, columns=[1])
print 'New DataFrame:'
print df
Original DataFrame:
1
0
078401115X 0
0790747324 0
0790750708 [(354, 1), (393, 1), (447, 1), (642, 1), (886,1)]
0800103688 0
5556167281 [(41, 1), (86, 1), (341, 1), (362, 1), (419, 10)]
6300157423 0
6300266850 0
6301699599 0
6301723465 0
Zero Indexes:
['078401115X', '0790747324', '0800103688', '6300157423', '6300266850', '6301699599', '6301723465']
New DataFrame:
1
0
078401115X [0.0, 0.0, 0.0, 0.0]
0790747324 [0.0, 0.0, 0.0, 0.0]
0790750708 [(354, 1), (393, 1), (447, 1), (642, 1), (886,1)]
0800103688 [0.0, 0.0, 0.0, 0.0]
5556167281 [(41, 1), (86, 1), (341, 1), (362, 1), (419, 10)]
6300157423 [0.0, 0.0, 0.0, 0.0]
6300266850 [0.0, 0.0, 0.0, 0.0]
6301699599 [0.0, 0.0, 0.0, 0.0]
6301723465 [0.0, 0.0, 0.0, 0.0]