csv读写文件

一、csv库

csv的操作是在文件操作内部进行的

（1）csv.reader(fp)
读取csv文件，每一行csv封装为一个列表，返回一个[[],[],[]…]包含多个（csv行数）列表的列表

import os
import numpy as np
import csv
import pandas
path = 'input/covid.test.csv'  # path to training data
#这里用with open 先打开文件，在转化格式
with open(path, 'r') as fp:
    #读取csv文件，每一行csv封装为一个列表，返回一个[[],[],[]...]包含多个（csv行数）列表的列表
    data = list(csv.reader(fp))
    data = np.array(data[1:])[:, 1:].astype(float)

（2）csv.writer（）
writer = csv.writer(csv_file, dialect=‘excel’) 建立写csv文件的writer
writer.writerow(row) 按行写入

def write_csv_file(path, head, data):
    try:
        with open(path, 'w') as csv_file:
            writer = csv.writer(csv_file, dialect='excel')
 
            if head is not None:
                writer.writerow(head)
 
            for row in data:
                writer.writerow(row)
 
            print("Write a CSV file to path %s Successful." % path)
    except Exception as e:
        print("Write an CSV file to path: %s, Case: %s" % (path, e))

解决内部含有空行的问题；
该问题解决方法：在open()内增加一个参数newline=’’ 即可，更改后代码结构如下：

def write_csv_file(path, head, data):
    try:
        with open(path, 'w', newline='') as csv_file:
            writer = csv.writer(csv_file, dialect='excel')
 
            if head is not None:
                writer.writerow(head)
 
            for row in data:
                writer.writerow(row)
 
            print("Write a CSV file to path %s Successful." % path)
    except Exception as e:
        print("Write an CSV file to path: %s, Case: %s" % (path, e))