我有一个凌乱的csv文件(只是扩展名为csv)。但是,当我以ms {exinited ;
开启此文件时,它看起来如下(虚拟样本) -
我调查了这个文件并找到了以下内容:
问题:
如何在pandas中读取此表,而所有现有列(标题)保留,空白列填充连续数字,可以控制行的可变长度。
事实上,我想一次又一次地获取8个单元格值,直到排出任何一行。从无标题列进行分析。
N.B。我在usecols
中尝试了names
,skiprows
,sep
,read_csv
等,但没有成功
添加了示例输入和预期输出(格式设置更糟,但pandas.read_clipboard(
)应该有效)
INPUT
car_id car_type entry_gate entry_time(ms) exit_gate exit_time(ms) traveled_dist(m) avg_speed(m/s) trajectory(x[m] y[m] speed[m/s] a_tangential[ms-2] a_lateral[ms-2] timestamp[ms] )
24 Bus 25 4300 26 48520 118.47 2.678999 509552.78 5039855.59 10.074 0.429 0.2012 0 509552.97 5039855.57 10.0821 0.3853 0.2183 20
25 Car 25 20 26 45900 113.91 2.482746 509583.7 5039848.78 4.5344 -0.1649 0.2398 0 509583.77 5039848.71
26 Car - - - - 109.68 8.859805 509572.75 5039862.75 4.0734 -0.7164 -0.1066 0 509572.67 5039862.76 4.0593 -0.7021 -0.1141 20 509553.17 5039855.55 10.0886 0.2636 0.2356 40
27 Car - - - - 119.84 3.075936 509582.73 5039862.78 1.191 0.5247 0.0005 0 509582.71 5039862.78 1.2015 0.5322
28 Car - - - - 129.64 4.347466 509591.07 5039862.9 1.6473 0.1987 -0.0033 0 509591.04 5039862.89 1.6513 0.2015 -0.0036 20
预期的输出(数据帧)
car_id car_type entry_gate entry_time(ms) exit_gate exit_time(ms) traveled_dist(m) avg_speed(m/s) trajectory(x[m] y[m] speed[m/s] a_tangential[ms-2] a_lateral[ms-2] timestamp[ms] 1 2 3 4 5 6 7 8 9 10 11 12
24 Bus 25 4300 26 48520 118.47 2.678999 509552.78 5039855.59 10.074 0.429 0.2012 0 509552.97 5039855.57 10.0821 0.3853 0.2183 20
25 Car 25 20 26 45900 113.91 2.482746 509583.7 5039848.78 4.5344 -0.1649 0.2398 0 509583.77 5039848.71
26 Car - - - - 109.68 8.859805 509572.75 5039862.75 4.0734 -0.7164 -0.1066 0 509572.67 5039862.76 4.0593 -0.7021 -0.1141 20 509553.17 5039855.55 10.0886 0.2636 0.2356 40
27 Car - - - - 119.84 3.075936 509582.73 5039862.78 1.191 0.5247 0.0005 0 509582.71 5039862.78 1.2015 0.5322
28 Car - - - - 129.64 4.347466 509591.07 5039862.9 1.6473 0.1987 -0.0033 0 509591.04 5039862.89 1.6513 0.2015 -0.0036 20
答案 0 :(得分:2)
<强>预处理强>
函数get_names()
打开文件,检查分割行的最大长度。
然后我读取第一行并从最大长度添加缺失值。
第一行的最后一个值为)
,因此我将其firstline[:-1]
删除,然后添加
按+1
rng = range(1, m - lenfirstline + 2)
排列缺少的列。
+2
是因为范围从值1
开始。
然后你可以使用函数read_csv
,skipp第一行和名称使用get_names()
的输出。
import pandas as pd
import csv
#preprocessing
def get_names():
with open('test/file.txt', 'r') as csvfile:
reader = csv.reader(csvfile)
num = []
for i, row in enumerate(reader):
if i ==0:
firstline = ''.join(row).split()
lenfirstline = len(firstline)
#print firstline, lenfirstline
num.append(len(''.join(row).split()))
m = max(num)
rng = range(1, m - lenfirstline + 2)
#remove )
rng = firstline[:-1] + rng
return rng
#names is list return from function
df = pd.read_csv('test/file.txt', sep="\s+", names=get_names(), index_col=[0], skiprows=1)
#temporaly display 10 rows and 30 columns
with pd.option_context('display.max_rows', 10, 'display.max_columns', 30):
print df
car_type entry_gate entry_time(ms) exit_gate exit_time(ms) \
car_id
24 Bus 25 4300 26 48520
25 Car 25 20 26 45900
26 Car - - - -
27 Car - - - -
28 Car - - - -
traveled_dist(m) avg_speed(m/s) trajectory(x[m] y[m] \
car_id
24 118.47 2.678999 509552.78 5039855.59
25 113.91 2.482746 509583.70 5039848.78
26 109.68 8.859805 509572.75 5039862.75
27 119.84 3.075936 509582.73 5039862.78
28 129.64 4.347466 509591.07 5039862.90
speed[m/s] a_tangential[ms-2] a_lateral[ms-2] timestamp[ms] \
car_id
24 10.0740 0.4290 0.2012 0
25 4.5344 -0.1649 0.2398 0
26 4.0734 -0.7164 -0.1066 0
27 1.1910 0.5247 0.0005 0
28 1.6473 0.1987 -0.0033 0
1 2 3 4 5 6 7 \
car_id
24 509552.97 5039855.57 10.0821 0.3853 0.2183 20 NaN
25 509583.77 5039848.71 NaN NaN NaN NaN NaN
26 509572.67 5039862.76 4.0593 -0.7021 -0.1141 20 509553.17
27 509582.71 5039862.78 1.2015 0.5322 NaN NaN NaN
28 509591.04 5039862.89 1.6513 0.2015 -0.0036 20 NaN
8 9 10 11 12
car_id
24 NaN NaN NaN NaN NaN
25 NaN NaN NaN NaN NaN
26 5039855.55 10.0886 0.2636 0.2356 40
27 NaN NaN NaN NaN NaN
28 NaN NaN NaN NaN NaN
<强>后处理强>
首先,您必须估算最大列数N
。我知道他们的真实数字是26
,所以我估计为N = 30
。参数read_csv
的函数name = range(N)
返回NaN
列,列的估计长度和实际长度之间存在差异。
删除后,您可以选择包含列名称的第一行,其中不是NaN
(我在)
删除了最后一列[:-1]
) - df1.loc[0].dropna()[:-1]
。
然后,您可以在第一行中添加范围从1到NaN
长度的新系列。
最后一行由df
的子集删除。
#set more as estimated number of columns
N = 30
df1 = pd.read_csv('test/file.txt', sep="\s+", names=range(N))
df1 = df1.dropna(axis=1, how='all') #drop columns with all NaN
df1.columns = df1.loc[0].dropna()[:-1].append(pd.Series(range(1, len(df1.columns) - len(df1.loc[0].dropna()[:-1]) + 1 )))
#remove first line with uncomplete column names
df1 = df1.ix[1:]
print df1.head()