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I'm working on a project that involves sending information from an ESP8266 by TCP/IP over telnet to python, and to be honest its my first time using telnetlib. I wrote this small code for testing, but when I execute it, it returns "'in ' requires string as left operand, not bytes". Can someone help me out please?

import telnetlib
HOST="192.168.0.67"
tn = telnetlib.Telnet(HOST, "23")

tn.write("Hello World\n")
print (tn.read_all())
Your_missing_bracket
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1 Answers1

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The read_all() method in telnetlib returns bytes rather than a string. You can verify this by reading the documentation for telnetlib.

print() takes a string as its argument - as the error you mentioned references. You'll need to convert the bytes returned by telnetlib.

Try using the str() function:

print (str(tn.read_all(), 'UTF-8'))

the UTF-8 argument specifies the encoding of the string, in this case 8 bit Unicode.

As an aside, Telnet is a deprecated protocol for doing remote login. It's a bit pointless to use it just to transfer data. You're better off using a raw TCP connection. Telnet is a thin layer above TCP that adds complexity and overhead you almost certainly do not need.

romkey
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