[Tutor] Open a text file, read and print pattern matching

[Steven D'Aprano]

tee chwee liong wrote:
> hi,
>  
> there is error when running the code:
>> Traceback (most recent call last):
>> File "C:/Python25/myscript/log/readfile9.py", line 5, in <module>
>> port, channel, lane, eyvt = line.split()
>> ValueError: need more than 2 values to unpack
> 
> the error is due to below line code:
>> port, channel, lane, eyvt = line.split()
>  
> pls advise. 


You have a line with only 2 words, and you are trying to unpack it into 
four variables. Four variables on the left, 4 values on the right works:

 >>> a, b, c, d = "sentence with four words".split()
 >>> print a
sentence
 >>> print b
with
 >>> print c
four
 >>> print d
words

But 4 variables on the left, 3 on the right does not:

 >>> a, b, c, d = "sentence with three".split()
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
ValueError: need more than 3 values to unpack

Likewise:

 >>> a, b, c, d = "two words".split()
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
ValueError: need more than 2 values to unpack

 >>> a, b, c, d = "word".split()
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
ValueError: need more than 1 value to unpack




-- 
Steven