python - 文件操作的方法

file文件使用流程：
1、打开文件 open("文件路径",mode='')
2、操作文件 file.read() 、file.write()
3、关闭文件 file.close()

''' mode = 'r'
read()
readline()
readlines()
'''
file1_1 = open(r'D:WorkSpacefunction_folderfile01.txt', mode='r',encoding='utf-8')
msg = file1_1.read()  # 一个字一个字的读取，直到读完所有内容
print("文件的内容：", msg)
file1_1.close()

file1_2 = open(r'D:WorkSpacefunction_folderfile01.txt', mode='r',encoding='utf-8')
msg = file1_2.readline(3)  # 读取指定的内容个数
print("文件的内容：", msg)
file1_2.close()

file1_3 = open(r'D:WorkSpacefunction_folderfile01.txt', mode='r',encoding='utf-8')
msg = file1_3.readlines()  # 按行读取，存入列表中
print("文件的内容：", msg)
file1_3.close()

file2 = open(r'D:WorkSpacefunction_folderfile01.txt', mode='w',encoding='utf-8')
file2.write("---写入的内容-----")
file2.close()

file3 = open(r'D:WorkSpacefunction_folderfile01.txt', mode='a',encoding='utf-8')
file3.write("---追加 写入的内容-----")
file3.close()

open(“文件路径”, mode=‘r+’,encoding=‘utf-8’)

file4 = open(r'D:WorkSpacefunction_folderfile01.txt', mode='r+',encoding='utf-8')
# 读
msg = file4.read()
print("文件内容1：", msg)
# 写
file4.write("====读写文件操作1====")
file4.close()

open(“文件路径”, mode=‘w+’,encoding=‘utf-8’)

file5 = open(r'D:WorkSpacefunction_folderfile01.txt', mode='w+',encoding='utf-8')
# 读
msg = file5.read()
print("文件内容2：", msg)   # 读取不到内容 因为w+的模式会清空文件
# 写
file5.write("====读写文件操作2====")
file5.close()

open(“文件路径”, mode=‘a+’,encoding=‘utf-8’)

file6 = open(r'D:WorkSpacefunction_folderfile01.txt', mode='a+',encoding='utf-8')
# 读
file6.seek(0)  # 将光标的位置移送到最开头就可以读取到了
msg = file6.read()
print("文件内容3：", msg)   # 读取不到内容 因为a+模式，属于追加文件内容，光标在文件末尾处
# 写
file6.write("====读写文件操作3====")
file6.close()

使用这个写法就不用担心忘记关闭文件了。如果在进行文件读取操作的时候忘记关闭文件，你会发现文件会报错或者出现乱码，打不开的情况

with open(r'D:WorkSpacefunction_folderfile01.txt', mode='r',encoding='utf-8') as file:
    msg = file.read()
    print("with  as  文件内容：", msg)

报错：UnicodeDecodeError: ‘gbk’ codec can’t decode byte 0xb9 in position 26: incomplete multibyte sequence
解决办法：open("文件路径",mode='',encoding='utf-8') 加入编码格式即可