CSV文件的header栏怎么写？

Question

def write_vt(d, filename):
    f = open(filename, 'w')

我应该以写入模式打开新文件，然后写入 header 列，然后使用 for 循环将数据字符串添加到文件中。但我就是不知道该怎么做...

原始文件名是votes.csv。

Answer 1

您可以使用它来添加 header：

header = "col1,col2,col3"
with open('file.csv','w') as my_csv:
    my_csv.write(header+'\n')

关于用数据填充您的 CSV，这将取决于您将用作源的原始数据。

Answer 2

有很多方法可以做到这一点，具体取决于您的数据和您愿意使用的工具：

a) 用列表和 header

逐行写入 CSV

import csv


data_list = [
    ["Russia", "Moscow", "Russian"],
    ["US", "Washington, D.C.", "English"],
    ["Colombia", "Bogotá", "Spanish"]
]
header = ["col1", "col2", "col3"]

def write_csv_from_lists(data, header, filename):
    with open(filename, "w") as csv_file:
        csv_writer = csv.writer(csv_file)
        csv_writer.writerow(header) # write header
        for row in data:
            csv_writer.writerow(row) # write each row

write_csv_from_lists(data_list, header, "file1.csv")

file1.csv

col1,col2,col3
Russia,Moscow,Russian
US,"Washington, D.C.",English
Colombia,Bogotá,Spanish

b) 用字典和 header

逐行写入 CSV

import csv


data_dict = [
    {"col1": "Russia", "col2": "Moscow", "col3": "Russian"},
    {"col1": "US", "col2": "Washington, D.C.", "col3": "English"},
    {"col1": "Colombia", "col2": "Bogotá", "col3": "Spanish"}
]
header = ["col1", "col2", "col3"]

def write_csv_from_dicts(data, header, filename):
    with open(filename, "w") as csv_file:
        dict_writer = csv.DictWriter(csv_file, fieldnames=header)
        dict_writer.writeheader() # write header
        for row in data:
            dict_writer.writerow(row) # write each row

write_csv_from_dicts(data_dict, header, "file2.csv")

file2.csv

col1,col2,col3
Russia,Moscow,Russian
US,"Washington, D.C.",English
Colombia,Bogotá,Spanish

c) 用 pandas

写入 CSV

import pandas as pd


data_dict = [
    {"col1": "Russia", "col2": "Moscow", "col3": "Russian"},
    {"col1": "US", "col2": "Washington, D.C.", "col3": "English"},
    {"col1": "Colombia", "col2": "Bogotá", "col3": "Spanish"}
]

def write_csv_pandas(data, filename):

    pd.DataFrame(data).to_csv(filename, index=False)

write_csv_pandas(data_dict, "file3.csv")

file3.csv

col1,col2,col3
Russia,Moscow,Russian
US,"Washington, D.C.",English
Colombia,Bogotá,Spanish

CSV文件的header栏怎么写？

How do you write in the header column for CSV file?

python

python-2.7

python-3.7

a) 用列表和 header

file1.csv

b) 用字典和 header

file2.csv

c) 用 pandas

file3.csv