[英]Manipulating data in csv using itertools (python)
我正在嘗試向下面的代碼添加功能,但似乎在某個地方搞砸了。
以下代碼基本上為以下每個揚聲器重復前“ z”個表列(如excel移調)。 對於這些在“ z”之后的列是日期,只需要一個日期列即可。
問題是python腳本正確生成了值,但需要它插入談論該日期的列,將此信息重復到該日期的所有值。
Python腳本:
from itertools chain from import
f = open ("C:\\Test.CSV", "r")
sep = ""
M = []
M = [M + [s.strip () for s in line.split (sep)] for line in f.readlines ()]
f.close ()
i = 0 # title
w = 4 # cols in title
r = 1 # body
z = 4 # fields fix
result = [M [i] [w] + ["date"] + ["Value"]] + list (chain (* [[x [: z] + [y] for y in x [z + 1: ]] for x in M [A:]]))
f = open ("C:\out.csv", 'w')
f.writelines ("\ n" .join ("". join (s) for s in result) + "\ 0")
f.close ()
東西(輸入):
[[X; y; date1; date2; date3]
[01; 02; 03; 04; 05]
[06; 07; 08; 09; 10]
[11; 12; 13, 14 15]]
當前腳本可以正確執行此操作(立即輸出):
[[X; y; date1]
[01; 02; 03]
[01; 02; 04]
[01; 02; 05]
[06; 07; 08]
[06; 07; 09]
[06; 07; 10]
[11; 12; 13]
[11; 12; 14]
[11; 12; 15]]
我的輸出是這個(期望的輸出):
[[X; y; date; value; ]
[01; 02; date1; 03]
[01; 02; date2; 04]
[01; 02; date3; 05]
[06; 07; date1; 08]
[06; 07; date2; 09]
[06; 07; date3; 10]
[11; 12; date1; 13]
[11; 12; date2; 14]
[11; 12; date3; 15]]
有人做過類似的事情嗎?
有什么原因不能只使用csv?
import csv
f = open("iter.csv", "r")
g = open("out.csv", "w", newline="")
transpose_columns = ['date1', 'date2', 'date3']
target_columns = ['date', 'value']
reader = csv.DictReader(f)
writer = csv.DictWriter(g, fieldnames=[a for a in reader.fieldnames
if a not in transpose_columns] + target_columns,
extrasaction='ignore')
writer.writeheader()
for row in reader:
for col in transpose_columns:
row[target_columns[0]] = col
row[target_columns[1]] = row[col]
writer.writerow(row)
f.close()
g.close()
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