Python-文件处理-读r写w操作参数

#读其他方法
  #readline

with open(r'f.txt',mode="tr",encoding="utf-8") as tr:
    res=tr.readline()  #每次读取文本文件一行，以换行符作为分隔符进行读取
    print(res)

#使用while循环每次读取文本文件一行
    while True:
        res=tr.readline()
        if len(res) == 0:
            break
        print(res)

#readlines

with open(r'f.txt',mode="tr",encoding="utf-8") as tr:
    res=tr.readlines()  #将内容一次性读入内存
    print(res)
    #['啦啦啦啦啦啦1啦啦2啦啦\n', '啦啦1\n', '啦啦2\n']

# 强调：
#read()与readlines()都是将内容一次性读入内存，如果内容过大会导致内存溢出。


#写其他方法:t模式

with open(r'i.txt', mode="tw", encoding="utf-8") as tw:
    # tw.write("111\n222\n333\n")
    l = ["111\n", "222", "333"]
    tw.writelines(l)
    等同于
    # l = ["111\n", "222", "333",444] #列表中元素必须是str类型的元素
    # for l_list in l:
    #     tw.write(l_list)

#写其他方法:b模式

print("111".encode("utf-8"))
#b'111'

等同于
bytes("上",encoding="utf-8") #字符串编码成bytes类型
#b‘111’

#使用encode()编码转换成bytes类型
with open(r'i.txt',mode="bw") as bw:
    l=["111\n".encode("utf-8"),"222".encode("utf-8"),"333".encode("utf-8")]
    bw.writelines(l)

#如果是纯英文字符，可以直接加前缀小b得到bytes类型
with open(r'i.txt',mode="bw") as bw:
    l=[b"111qq\n",b"222bb",b"333cc"]
    bw.writelines(l)

#中文字符bytes("上".encode("utf-8"))得到bytes类型
with open(r'i.txt',mode="bw") as bw:
    l=[bytes("上啊\n".encode("utf-8")),bytes("哈哈".encode("utf-8")),bytes("嘿嘿".encode("utf-8"))]
    bw.writelines(l)

#flush
with open(r'i.txt',mode="bw") as bw:
    l=[bytes("上啊\n".encode("utf-8")),bytes("哈哈".encode("utf-8")),bytes("嘿嘿".encode("utf-8"))]
    bw.writelines(l) #将内存的数据交给操作系统
    bw.flush()  #将操作系统数据立马刷新到硬盘中

#了解:其它方法
with open(r'i.txt',mode="bw") as bw:
    print(bw.readable())
    # False
    print(bw.writable())
    #True
    print(bw.closed)
    #False
    print(bw.name)
    #i.txt
print(bw.closed)
#True