【1】python csv模块 随笔

 csv格式的文件是不包含格式的，而且是不存在sheet表这一个概念的

fp = open('ces.csv',newline='')

with open('ces.csv', newline='') as fp:

open()函数 打开文件 ，如果没有则自动创建该文件 ，”w"代表写入，”newline"如果不加newline，则会在每一行插入之后添加一个空行

首先在文件里面创建几条数据

 读数据

fp = open('ces.csv', newline='')
reader = csv.reader(fp)
for row in reader:
    print(row)

# ['序号', '数字']
# ['1', '3']
# ['2', '4']

写入数据

!注意：每次写入数据都会清除所有的数据

列表的写入

# 列表的写入
#     单行写入
f = open('ces.csv','w',newline='')
fp = csv.writer(f)
data = [7,8]
fp.writerow(data)
#     多行写入
data = [['Tom', '25', '1367890900'], ['Jim', '18', '1367890800']]
fp.writerows(data) # 多行写入要加s，writerrows
with open('ces.csv', newline='') as f:
    fp = csv.reader(f)
    for row in fp:
        print(row)

# ['7', '8']
# ['Tom', '25', '1367890900']
# ['Jim', '18', '1367890800']

 字典的写入

# 字典的写入
data = [{'name': 'Bob', 'age': 23}, {'name': 'Jerry', 'age': 44}, {'name': 'Tom', 'age': 15}]
with open('ces.csv', 'w', newline='') as f:
    fp = csv.DictWriter(f, ['name', 'age']) # 定义表头
    fp.writeheader() # 写入表头
    for row in data:
        # fp.writerow(row)
        fp.writerows(data)

with open('ces.csv', 'r') as f:
    fp = csv.DictReader(f)
    for row in fp:
        print(row['name'], row['age'])

# Bob 23
# Jerry 44
# Tom 15
# Bob 23
# Jerry 44
# Tom 15
# Bob 23
# Jerry 44
# Tom 15

如有错误，请多指正！