python 14 文件处理

# python 文件处理
# /usr/sbin/py/python
# -*-coding:utf8-*-
inner = open("a/document.txt")  # 这种方式打开的文件默认是读模式
eqInner = open("a/document.txt", "r")  # 等同于上式  文件的打开模式 r：只读 w：只写 a：追加
print(eqInner.read())
eqInner.close()
a = inner.read()
print(a)
inner.close()
text = open("a/测试文件.txt", encoding="utf8")  # 当文件名为汉语时需要指定编码
print(text.readline())
print(text.readline())
print("------------------>")
innerText = text.read()
print(innerText)  # 同一个stream中文件内容读出去了，再读，就没有了
print(text.readable())  # 是否是可读的  r：true  w：false
text.close()
winner = open("a/documentTest.txt", "w", encoding="utf8")  # 写模式 如果文件存在会将文件中的内容清空然后再写入，不存在则创建
winner.write("hello ")
winner.writelines("jake\n")
winner.writelines("where is tom?")

ainner = open("a/document.txt", "a", encoding="utf8")
ainner.writelines("jake")

rAndw = open("a/abc.txt", "r+", encoding="utf8")
data = rAndw.read()
print(data)
rAndw.write("额")
rAndw.close()

with open("a/abc.txt", "r", encoding="utf8") as f:
    print(f.read())

# python 以字节的方式操作文件
f1 = open("a/字节.txt", "rb")
data = f1.read()
print(data.decode("utf8"))

f2 = open("a/字节写入.txt", "wb")
f2.write("jake".encode("utf8"))
f2.write(bytes("tom", encoding="utf8"))
f2.close()
# python 测试回车
f3 = open("a/回车.txt", "r", encoding="utf8")
print(f3.readlines())
f3.close()
f4 = open("a/回车.txt", "r", encoding="utf8", newline="")  # 不用python自动转换，自动输出
print(f4.tell())  # 获取读取位置
print(f4.seek(3))  # 跳过几个字符
print(f4.readlines())
# f4.truncate(10)  # 截断 取前10个字节
f4.close()
# seek 方法三种模式
f5 = open("a/seek.txt", "rb")
f5.seek(-10, 2)  # 2 表示倒着数十个字节
print(f5.tell())
print(f5.read())
f5.close()
# 读取最后一行
f6 = open("a/seek.txt", "rb")
data = f6.readlines()  # 这样读虽然也能获取最后一行，但无用数据全部加载到了内存，性能极差
print(data)
print(data[-1].decode("utf8"))
f6.close()

f7 = open("a/seek.txt", "rb")
# 循环文件
for i in f7:    # 这种取法用到才会加载到内存
    offset = 10
    while True:
        f7.seek(-offset, 2)
        data = f7.readlines()
        if len(data) > 1:
            print(data[-1].decode("utf8"))
            break
        else:
            offset *= 2

来源：CSDN

作者：XiaoqiangNan

链接：https://blog.csdn.net/XiaoqiangNan/article/details/104360567