Python CSV 模块的用法

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python csv module的用法。

读取csv文件的代码

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import csv

def csv_reader(file_obj):
  """Read a csv file"""
  reader = csv.reader(file_obj)
  for row in reader:
    print(" ".join(row))

if __name__ == '__main__':
  csv_path = 'filename.csv'
  with open(csv_path, 'r') as file_obj:
    csv_reader(file_obj)

使用DictReader读取csv文件

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import csv

def csv_dict_reader(file_obj):
  """Read a CSV file using csv.DictReader"""
  reader = csv_DictReader(file_obj, delimeter=',')
  for line in reader:
    print(line['colume-name'])

if __name__ == '__main__':
  with open('filename.csv') as file_obj:
    csv_dict_reader(file_obj)

写入CSV文件

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import csv

def csv_writer(data, path):
  with open(path, 'w', newline='') as csv_file:
    for line in data:
      writer.writerow(line)

if __name__ == '__main__':
  data = ['first_name', 'last_name', 'city'.split(','), ...]
  path = 'output.csv'
  csv_writer(data, path)

用DictWriter写入CSV文件

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import csv

def csv_dict_writer(path, field_names, data):
  """Write a CSV file using DictWriter"""
  with open(paht, 'w', newline='') as out_file:
    writer = csv.DictWriter(out_file, delimeter=',', field_names=filenames)
    writer.writeheader()
    for row in data:
      writer.writerow(row)

if __name__ == '__main__':
  data = ['first_name', 'last_name', 'city'.split(','), ...]
  my_list = []
  field_names = data[0]
  for values in data[1:]:
    inner_dict = dict(zip(field_names, values))
    my_list.append(inner_dict)

  path = 'dict_output.csv'
  csv_dict_writer(path, field_names, my_list)
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