Question

我正在读取多个csv文件，并将其组合到一个csv文件中。合并数据的预期结果如下所示：

0   4   6   8   10  12
1   2   5   4   2   1  
5   3   0   1   5   10
....

但是，在下面的代码，我打算列从0,4,6,8,10,12去。

for indx, file in enumerate(files_File1):
    if file.endswith('csv'):  #reading csv filed in the designated folder
        filepath = os.path.join(folder_File1, file) #reading csv filed in the designated folder
        current = pd.read_csv(filepath, header=None) #reading csv filed in the designated folder
        if indx == 0:
            mydata_File1 = current.copy()
            mydata_File1.columns.values[1] = 4
            print(mydata_File1.columns.values)
        else:
            mydata_File1[2*indx+4] = current.iloc[:,1]
            print(mydata_File1.columns.values)

但是，结果看起来像这样，列从0,2,4,6,8,10,12开始。

0   4   2   6   8   10  12
1   2       5   4   2   1  
5   3       0   1   5   10
....

我不太确定是什么原因导致列名为“ 2”。

有什么主意吗？

Answer 1

如果您真的只是想合并.csv文件，则不需要熊猫。

#! python3
import glob

folder_File1 = r"C:\Users\Public\Documents\Python\CombineCSVFiles"
csv_only = r"\*.csv"
files_File1 = glob.glob(f'{folder_File1}{csv_only}')
new_csv = f'{folder_File1}\\newcsv.csv'

lines = []
for file in files_File1:
    with open(file) as filein:
        if filein.name == new_csv:
            pass
        else:
            for line in filein:
                line = line.strip()  # or some other preprocessing
                lines.append(line)  # storing everything in memory!

with open(new_csv, 'w') as out_file:
    out_file.writelines(line + u'\n' for line in lines)

Answer 2

如果出于某些原因需要熊猫，则可以使用。您的代码引用了mydata_File1.columns.values，它是列的名称，而不是列中的值。如果这不能回答您的问题，请根据@ juanpa.arrivillaga的评论提供更完整的答案。

#! python3
import os
import pandas as pd
import glob

folder_File1 = r"C:\Users\Public\Documents\Python\CombineCSVFiles"
csv_only = r"\*.csv"
files_File1 = glob.glob(f'{folder_File1}{csv_only}')
new_csv = f'{folder_File1}\\newcsv.csv'


mydata_File1 = []

for indx, file in enumerate(files_File1):
    if file == new_csv:
        pass
    else:
        current = pd.read_csv(file, header=None) #reading csv filed in the designated folder
        print (current)
        if indx == 0:
            mydata_File1 = current.copy()
            print(mydata_File1.values)
        else:
            pass
            mydata_File1 = mydata_File1.append(current, ignore_index=True)
            print(mydata_File1.values)

mydata_File1.to_csv(new_csv)

Python的for循环枚举

2 个答案: