如何在这个Python脚本中处理CSV文件。

Question

再用花的CSV文件，填入contents_of_file函数的空白处处理数据，不需要把它变成字典。如何跳过字段名的头记录？

import os
import csv

# Create a file with data in it
def create_file(filename):
    with open(filename, "w") as file:
        file.write("name,color,type\n")
        file.write("carnation,pink,annual\n")
        file.write("daffodil,yellow,perennial\n")
        file.write("iris,blue,perennial\n")
        file.write("poinsettia,red,perennial\n")
        file.write("sunflower,yellow,annual\n")

# Read the file contents and format the information about each row
def contents_of_file(filename):
    return_string = ""
    # Call the function to create the file 
    create_file(filename)

    # Open the file
    with open(filename) as file:
        # Read the rows of the file
        rows = csv.reader(file)
        rows = list(rows)
        # Process each row
        for row in rows:
            name, color, ty = row
            # Format the return string for data rows only
            if row != rows[0]:
                return_string += "a {} {} is {}\n".format(name, color, ty)
    return return_string

#Call the function
print(contents_of_file("flowers.csv"))

提交答案后，显示以下信息。

Not quite, contents_of_file returned:
a carnation pink is
annual
a daffodil yellow is perennial
a iris blue is
perennial
a poinsettia red is perennial
a sunflower yellow
is annual

The output should be:
a pink carnation is annual
a yellow daffodil is perennial
a blue iris is perennial
a
red poinsettia is perennial
a yellow sunflower is annual

如何纠正这个问题？

Answer 1

你可以在实例化这个函数之前，通过读入并丢弃这一行来跳过 csv.reader 对象，或者你可以直接丢弃第一行，将其转换为一个列表并从1开始循环。

  with open(filename) as file:
    file.readline()  # header row
    for row in csv.reader(file):
      # do stuff

或者你可以直接丢弃第一行 通过转换为一个列表并从1开始循环。

  with open(filename) as file:
    for row in list(csv.reader(file))[1:]:
      # do stuff

或者像这样，如果你想在迭代器上循环，而不把所有的行加载到内存中。

  with open(filename) as file:
    first = True
    for row in csv.reader(file):
      if first:
         first = False
         continue
      # do stuff

或者你可能更喜欢使用csv阅读器的字典形式，这样你就不会丢弃头行，而是用它来提供字典键。

  with open(filename) as file:
    for row in csv.DictReader(file):
      # row is now a dictionary, e.g.
      # {'color': 'pink', 'type': 'annual', 'name': 'carnation'}
      # do stuff

Answer 2

改变

return_string += "a {} {} is {}\n".format(name, color, ty)

至

return_string += "a {} {} is {}\n".format(color, name, ty)

Answer 3

为了解决" 如何跳过带有字段名的头记录？"的问题。可以使用next()。

with open('my_file.csv', 'r') as f:
    headers = next(f)
    # do something with rest of the lines