python3之文件的read、readline和readlines

最新推荐文章于 2024-07-13 22:56:39 发布

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#python #文件读取

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本文详细介绍了Python中文件读取的各种方法，包括read(), readline(), readlines()等，通过实例展示了如何使用这些方法来读取文件的不同部分，适合初学者和需要复习Python文件操作的开发者。

部署运行你感兴趣的模型镜像

test.txt内容：

aaaa
bbbb
cccc

示例：

read

read()

with open('test.txt') as f:
    # read()读取所有
    a1 = f.read()  # str
    print(a1)

output:

aaaa
bbbb
cccc

read(size)

with open('test.txt') as f:
    datas = []
    # read([size])指定读取的字节数，包括\n
    a1 = f.read(3)  # str
    while a1:
        # 每次读取内容保存至datas
        datas.append(a1)
        a1 = f.read(3)
# 输出每次读取的内容
print(datas)

output:

[‘aaa’, ‘a\nb’, ‘bbb’, ‘\ncc’, ‘cc\n’]

readline

readline()

with open('test.txt') as f:
    datas = []
    # readline每次读取一行
    a2 = f.readline()  # str
    while a2:
        datas.append(a2)
        a2 = f.readline()
    print('readline():')
    print(datas)

output:

[‘aaaa\n’, ‘bbbb\n’, ‘cccc\n’]

readline(size)

with open('test.txt') as f:
    datas = []
    # readline每次读取一行
    # 指定读取字节数
    a2 = f.readline(3)  # str
    while a2:
        datas.append(a2)
        a2 = f.readline(3)
    print('readline(size):')
    print(datas)

output:

[‘aaa’, ‘a\n’, ‘bbb’, ‘b\n’, ‘ccc’, ‘c\n’]

readlines

readlines()

with open('test.txt') as f:
    # readlines一次读取所有行，返回列表
    a3 = f.readlines()  # list
    print('readlines():')
    print(a3)

output:

[‘aaaa\n’, ‘bbbb\n’, ‘cccc\n’]

readlines(size)???

with open('test.txt') as f:
    a3 = f.readlines(1)  # list
    print('readlines(1):')
    print(a3)
    a3 = f.readlines(2)  # list
    print('readlines(2):')
    print(a3)
    a3 = f.readlines(3)  # list
    print('readlines(3):')
    print(a3)
    a3 = f.readlines(4)  # list
    print('readlines(4):')
    print(a3)