python文件操作一（read，write）

加b的区别

r,w的方式就是读写纯文本
rb，wb是读写各种内容，以二进制的方式

read

read(“path”,“r”)默认是r
假设文本为

aaa
bbb

stream = open("test.txt")
container = stream.read()
print(container)

结果

aaa
bbb

readable

是否可以读取

result = stream.readable()
print(result)

结果

True

readline

读取一行

line = stream.readline()
print(line)

结果

aaa

readlines

读取多行

lines = stream.readlines()
print(lines)

结果在列表里

["aaa","bbb"]

write

read(“path”,“w”)默认是w

stream = open("test.txt", "w")
# a 追加
s = """
aslnfdov fdknvb
jn
"""
stream.write(s)
stream.write("rfffff")
stream.writelines(['rfffff\n', 'ssss\n', 'dddd\n'])
stream.close()

这种方式会覆盖源文件，如果没有目录会自动创建，只要不close就可以一直输入，结果为

aslnfdov fdknvb
jn
rfffff

writelines

直接插入多行

stream = open("test.txt", "w")
stream.writelines(['rfffff\n', 'ssss\n', 'dddd\n'])
stream.close()

结果

rfffff
ssss
dddd

追加方式

用a，这样不会覆盖原文件

stream = open("test.txt", "a")

with

使用with避免忘记close，可以自动释放，例子

with open("test.txt","rb") as f:
    txt = f.read()

文件复制

将test文件复制到test2

with open("test.txt", "rb") as f:
    txt = f.read()
    with open("test2.txt", "wb") as w:
        w.write(txt)