file - Python error message io.UnsupportedOperation: not readable

Question

I made a simple program but It shows the following error when I run it:

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("
")

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

It shows this error message:

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

UnsupportedOperation: not readable

Answer 1

You are opening the file as "w", which stands for writable.

Using "w" you won't be able to read the file. Use the following instead:

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

Additionally, here are the other options:

"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.