In-memory Streams



In [1]:

    
output.write('This goes into the buffer. ')
print('And so does this.', file=output)

# Retrieve the value written
print(output.getvalue())

output.close()  # discard buffer memory

# Initialize a read buffer
input = io.StringIO('Inital value for read buffer')

# Read from the buffer
print(input.read())









    



This goes into the buffer. And so does this.

Inital value for read buffer

To work with raw bytes instead of Unicode text, use BytesIO.



In [2]:

    
import io

# Writing to a buffer
output = io.BytesIO()
output.write('This goes into the buffer. '.encode('utf-8'))
output.write('ÁÇÊ'.encode('utf-8'))

# Retrieve the value written
print(output.getvalue())

output.close()  # discard buffer memory

# Initialize a read buffer
input = io.BytesIO(b'Inital value for read buffer')

# Read from the buffer
print(input.read())









    



b'This goes into the buffer. \xc3\x81\xc3\x87\xc3\x8a'
b'Inital value for read buffer'

Wrapping Byte Streams for Text Data

Raw byte streams such as sockets can be wrapped with a layer to handle string encoding and decoding, making it easier to use them with text data. The TextIOWrapper class supports writing as well as reading. The write_through argument disables buffering, and flushes all data written to the wrapper through to the underlying buffer immediately.



In [3]:

    
import io

# Writing to a buffer
output = io.BytesIO()
wrapper = io.TextIOWrapper(
    output,
    encoding='utf-8',
    write_through=True,
)
wrapper.write('This goes into the buffer. ')
wrapper.write('ÁÇÊ')

# Retrieve the value written
print(output.getvalue())

output.close()  # discard buffer memory

# Initialize a read buffer
input = io.BytesIO(
    b'Inital value for read buffer with unicode characters ' +
    'ÁÇÊ'.encode('utf-8')
)
wrapper = io.TextIOWrapper(input, encoding='utf-8')

# Read from the buffer
print(wrapper.read())









    



b'This goes into the buffer. \xc3\x81\xc3\x87\xc3\x8a'
Inital value for read buffer with unicode characters ÁÇÊ



In [ ]: