文件处理file handling

#1. 打开文件，得到文件句柄并赋值给一个变量
#2. 通过句柄对文件进行操作
#3. 关闭文件

#1、open函数打开文件，open找的是系统的编码gbk
f = open("陈粒",encoding="utf-8") #打开文件指定编码
data = f.read() #读的模式
print(data)
f.close()   #关闭文件
f = open("xxx")
data = f.read()
print(data)
f.close()
#2、r是读的方式,readable是判断是否可读
f = open("陈粒","r",encoding="utf-8")
print(f.readable()) #
#3、readline默认一次读取一行
f = open("陈粒",encoding="utf-8")
print("第一行",f.readline(),end="")
print("第二行",f.readline(),end="")
print("第三行",f.readline(),end="")
print("第四行",f.readline(),end="")
print("第五行",f.readline(),end="")
print("第六行",f.readline(),end="")
print("第七行",f.readline(),end="")
f.close()
print("读的模式已结束")
#4、写模式只能写不能读、读模式只能读不能写
#5、w模式是把文件内容清空掉再执行操作如果文件不存在的话再重新新建一个文件
f = open("陈粒1","w",encoding="utf-8")
f.write("11111\n")
f.write("22222\n")
f.write("33333\n")
f.write("44444\n")  #\n回车加换行
f.writelines(["555\n","666\n"])
f.close()
print("写的模式已结束")
#6、writable判断是否可写
#7、writelines写入行
#8、追加模式用a
f = open("陈粒1","a",encoding="utf-8")
f.write("写到最后")
f.close()
print("追加模式已结束了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了了")
#9、r+读写模式
f = open("xxx","r+",encoding="utf-8")
data = f.read()
print(data)
f.write("123")
f.close()
#10、r读的方式打开文件，w写的方式到新文件
src_f = open("xxx","r",encoding= "utf-8")
data = src_f.readlines()
src_f.close()
print(data)
dst_f = open("xxx_new","w",encoding="utf-8")
dst_f.write(data[0])
dst_f.close()
#11、with用法一：
with open("a.txt","w") as f:
    f.write("1111\n")
#12、with用法二：
# src_f = open("xxx","r",encoding="utf-8")
# dst_f = open("xxx","w",encoding="utf-8")
with open("xxx","r",encoding="utf-8") as src_f,\
        open("xxx_new","w",encoding="utf-8") as dst_f:
    data = src_f.read()
    dst_f.write(data)

#13、
l = [1,2,3,4,5]
print(list(map(str,l)))
#14、
from functools import reduce
l = [1,2,3,4,5]
print(reduce(lambda x,y : x + y,l,3))
#15、过滤下划线_xx的元素
name = ["zd_xx","zs"]
a = filter(lambda x:not x.endswith("_xx"),name)
print(list(a))
#16、map函数是对每个元素处理返回同等元素，filter函数是过滤每个元素返回过滤的结果，reduce函数是对很多个元素处理返回一个元素
#17、r模式读、a模式追加、w模式覆盖并追加
#18、b方式以字节的方式操作
#f = open("test11.py","rb",encoding="utf-8")
f = open("test11.py","rb")
data = f.read()
print(data) #结果是字节形式
print(data.decode("utf-8"))# 把二进制转成字符串形式
#19、windows平台中\r\n是回车的意思，Linux平台中回车是\n
#20、"字符串"----------------encode-------------》bytes
#21、"bytes"----------------decode-------------》字符串
#22、wb是二进制方式
#23、把字符串转换成bytes类型
x ="hello"
print(bytes(x,encoding="utf-8"))
#24、把字符串转换成二进制是编码的过程
a = "张达".encode("utf-8")
print(a)
#25、closed判断文件状态是否关闭
f = open("a.txt","w")
print(f.closed)
#26、encoding取自文件打开的编码
print(f.encoding)
#27、cp936是gbk的
#28、latin-1拉丁编码
f = open("a.txt","r+",encoding="utf-8")
print(f.readlines())
print("结束了")
#29、flush刷新
#30、tell光标读取
print(f.tell())
f.readline()
print(f.tell())
#31、seek控制光标移动
#32、
f.seek(3)
print(f.read())
#33、truncate截断
print("上面的已结束")
#34、
f = open("seek.txt","r",encoding="utf-8")
print(f.tell())
f.seek(10)
print(f.tell())
f.seek(3)
print(f.tell())