python-3.x - Python 错误消息 io.UnsupportedOperation : not readable

Question

我做了一个简单的程序，但是当我运行它时显示以下错误:

line1 = []
line1.append("xyz ")
line1.append("abc")
line1.append("mno")

file = open("File.txt","w")
for i in range(3):
    file.write(line1[i])
    file.write("\n")

for line in file:
    print(line)
file.close()

它显示此错误消息:

File "C:/Users/Sachin Patil/fourth,py.py", line 18, in
for line in file:

UnsupportedOperation: not readable

Answer 1

您正在以 "w" 的身份打开文件，代表可写。
使用 "w"您将无法读取该文件。请改用以下内容:

file = open("File.txt","r")

此外，这里是其他选项:

"r"   Opens a file for reading only.
"r+"  Opens a file for both reading and writing.
"rb"  Opens a file for reading only in binary format.
"rb+" Opens a file for both reading and writing in binary format.
"w"   Opens a file for writing only.
"a"   Open for writing.  The file is created if it does not exist.
"a+"  Open for reading and writing.  The file is created if it does not exist.