Stream

Opening a file for writing.

# w means open in write mode
with open('example.txt', 'w') as file:
    file.write("Hello, world!\n")

File will be created when it does not exist.

When file does not exist, it will be exmptied before writing (override).

Reading a file:

with open('example.txt', 'r') as file:
    content = file.read()

    print(content)

Reading by line by line:

with open('example.txt', 'r') as file:
    for line in file:
        print(line, end='')

for line in file iterates over each line in the file.

end='' is used to prevent adding an extra newline character after each line (since each file line already ends with a newline character).

In-memory TEXT Stream

from io import StringIO

# Create an in-memory text stream
text_stream = StringIO()

# Write to the in-memory stream
text_stream.write("This is a text stream example.\n")
text_stream.write("It behaves like a file object.\n")

# Move to the beginning of the stream
text_stream.seek(0)

# Read from the in-memory stream
content = text_stream.read()
print(content)

In-memory Binary Stream

from io import BytesIO

# Create an in-memory binary stream
binary_stream = BytesIO()

# Write binary data to the in-memory stream
binary_stream.write(b'This is a binary stream example.\n')
binary_stream.write(b'It behaves like a file object.\n')

# Move to the beginning of the stream
binary_stream.seek(0)

# Read binary data from the in-memory stream
content = binary_stream.read()
print(content)