python - 使用 Python 在 CSV 文件中添加列

Question

我有如下所示的 csv 文件(输入文件):

Temperature,2,3
Temperature,5,6
Pressure,11,14,45
Pressure,13,23,16
Humidity,21,24,25
Humidity,27,28,26

我想将它写入另一个文件(输出文件)，但格式如下:

Temperature,2,3,Pressure,11,14,45,Humidity,21,24,25
Temperature,5,6,Pressure,13,23,16,Humidity,27,28,26

我试过以下 Python 代码:

with open('inputFile.csv','r') as csvinput:
	with open('outputFile.csv','w') as csvoutput:
		writer = csv.writer(csvoutput, delimiter= ',')
		writer = csv.writer(csvoutput)
		for row in csv.reader(csvinput):
			if (row[0] == "Pressure" or row[0] == "Humidity"):
				type =row[0]
				Value = row[1])
	        writer.writerow(row + [np.asarray(type)] + [np.asarray(Value)])

输出格式如下:

Temperature,2,3,Humidity,27

Temperature,5,6,Humidity,27

Temperature,8,9,Humidity,27

Pressure,11,14,45,Pressure,11

Pressure,13,23,16,Pressure,13

Humidity,21,24,25,Humidity,21

Humidity,27,28,26,Humidity,27

请帮忙!

Answer 1

缺少二进制模式。

为了提高可读性，我建议将读取、更改数据和写入分开，因为您必须在写入之前读取整个输入文件。

示例(没有错误处理):

  import csv
  f = open('inputFile.csv','rb')
  reader = csv.reader(f)
  data = {}
  keys = set ()
  for row in reader : 
    key = row [0]
    data.setdefault (key, []).append (row) 
  f.close ()
  odata = []
  for (t, p, h) in zip (data ["Temperature"], data ["Pressure"], data   ["Humidity"]) :
    odata.append (t + p + h)
  g = open('outputFile.csv','wb')
  writer = csv.writer (g)
  writer.writerows (odata)
  g.close ()