使用python追加csv文件數據

Question

我一直在嘗試使用 python 將 input.csv 中的某些數據附加到 output.csv 中。

我的代碼如下：

    import csv
    from csv import writer
    from csv import reader
    
    
    csvPath = r'C:\Users\Nitin Kumar\Downloads\annual-enterprise-survey-2020-csv-new.csv'
    csvWrite = r'C:\Users\Nitin Kumar\Downloads\copied.csv'
    
    rslt=[]
    with open(csvPath, encoding='utf-8-sig') as csvfile:
    reader = csv.reader(csvfile)

    count=0
    fsa=[]
    for row in reader:
        count=count+1
        print(row)
        rslt.append(row)
        # if count>20:
        #     break
print(rslt)

with open(csvPath, 'r') as read_obj, \
        open(csvWrite, 'a', newline='') as write_obj:
    csv_reader = csv.reader(read_obj)
    csv_writer = csv.writer(write_obj)
    for row_ in csv_reader:
        row_.append(rslt)
        csv_writer.writerow(row_)

輸入的 csv 文件是：

    Year,Industry_agg,Industry_code,Industry_name,Units,Variable_code,Variable_name,Variable_category,Value,Industry_code_ANZSIC06
    2020,Level 1,99999,All industries,Dollars (millions),H01,Total income,Financial performance,"7,33,258",ANZSIC06 divisions A-S 
    2020,Level 1,99999,All industries,Dollars (millions),H04,Sales,Financial performance,"6,60,630",ANZSIC06 divisions A-S
    2020,Level 1,99999,All industries,Dollars (millions),H05,"Interest, dividend",Financial performance,"54,342",ANZSIC06 divisions A-S 
    2020,Level 1,99999,All industries,Dollars (millions),H07,Non-operating income,Financial performance,"18,285",ANZSIC06 divisions A-S
    2020,Level 1,99999,All industries,Dollars (millions),H08,Total expenditure,Financial performance,"6,54,872",ANZSIC06 divisions A-S

我得到的輸出文件是：

    Name
    Nitin
    Nitin1
    Nitin2
    Nitin3
    Nitin4
    Nitin5
    Year,Industry_agg,Industry_code,Industry_name,Units,Variable_code,Variable_name,Variable_category,Value,Industry_code_ANZSIC06,[]
    2020,Level 1,99999,All industries,Dollars (millions),H01,Total income,Financial performance,"7,33,258",ANZSIC06 divisions A-S ,[]
    2020,Level 1,99999,All industries,Dollars (millions),H04,Sales,Financial performance,"6,60,630",ANZSIC06 divisions A-S,[]
    2020,Level 1,99999,All industries,Dollars (millions),H05,"Interest, dividend",Financial performance,"54,342",ANZSIC06 divisions A-S ,[]
    2020,Level 1,99999,All industries,Dollars (millions),H07,Non-operating income,Financial performance,"18,285",ANZSIC06 divisions A-S,[]
    2020,Level 1,99999,All industries,Dollars (millions),H08,Total expenditure,Financial performance,"6,54,872",ANZSIC06 divisions A-S ,[]

但是，輸出 csv 文件在附加數據之前具有以下數據：

    Name
    Nitin
    Nitin1
    Nitin2
    Nitin3
    Nitin4
    Nitin5

我需要輸出文件如下所示：

    Name,Year,Industry_agg,Industry_code,Industry_name,Units,Variable_code,Variable_name,Variable_category,Value,Industry_code_ANZSIC06
    Nitin,2020,Level 1,99999,All industries,Dollars (millions),H01,Total income,Financial performance,"7,33,258",ANZSIC06 divisions A-S 
    Nitin1,2020,Level 1,99999,All industries,Dollars (millions),H04,Sales,Financial performance,"6,60,630",ANZSIC06 divisions A-S
    Nitin2,2020,Level 1,99999,All industries,Dollars (millions),H05,"Interest, dividend",Financial performance,"54,342",ANZSIC06 divisions A-S 
    Nitin3,2020,Level 1,99999,All industries,Dollars (millions),H07,Non-operating income,Financial performance,"18,285",ANZSIC06 divisions A-S
    Nitin4,2020,Level 1,99999,All industries,Dollars (millions),H08,Total expenditure,Financial performance,"6,54,872",ANZSIC06 divisions A-S
    Nitin5

我需要我的輸出文件來附加輸入數據，但無法獲得所需的結果。 以前我什至可以在 outout csv 文件中添加標題。 經歷了很多已經存在的代碼，但沒有一個對我有幫助。

Answer 1

合並輸入和輸出文件的行，並用新行覆蓋輸出文件。

# read input file
with open(input_filename, 'r') as input_file:
    input_lines = input_file.read().split('\n')
    input_lines.append('') # because your input file has 
                           # one less line than your output file
    
# read output file
with open(output_filename, 'r') as output_file:
    output_lines = output_file.read().split()

# combine lines of input and output files
new_lines = [output_line + ',' + input_line for 
             input_line, output_line in zip(input_lines, output_lines)]

# overwrite output file with new lines
with open(output_filename, 'w') as output_file:
    for i, line in enumerate(new_lines):
        end = '\n' if i + 1 < len(new_lines) else '' # make new line except 
                                                     # after last line
        output_file.write(line + end)

Answer 2

您可能會發現使用 Python 的zip_longest()函數會更好，該函數能夠輕松處理不同長度的列表。

嘗試以下操作：

import csv
from itertools import zip_longest

csvPath = r'C:\Users\Nitin Kumar\Downloads\annual-enterprise-survey-2020-csv-new.csv'
csvWrite = r'C:\Users\Nitin Kumar\Downloads\copied.csv'

# Read all the existing entries
existing = []       # Rows holding: Name, Nitin, Nitin1

with open(csvWrite, encoding='utf-8-sig') as f_existing:
    existing = list(csv.reader(f_existing))

# Read the new entries and combine with the existing entries
with open(csvPath, 'r') as f_input, \
    open(csvWrite, 'w', newline='') as f_output:
    
    csv_input = csv.reader(f_input)
    csv_output = csv.writer(f_output)
    
    for row_existing, row_new in zip_longest(existing, csv_input, fillvalue=''):
        csv_output.writerow([*row_existing, *row_new])

最后一行從現有行中獲取所有元素並將它們與新行中的所有元素組合以創建組合輸出列表行。