Decode the hidden message!
Python 3, 98



lambda l:''.join(x*('='!=x[1:-1])for x in l).translate({'='!=x[1:-1]or ord(x[0]):x[2:]for x in l})


This lambda function receives a list of strings (input) and returns a string (the decoded message).

Examples:

&gt;&gt;&gt; f(['ta', 'y=s', 'y', 'a=e', 'b=t', 'b', ' ', 'j', 'j=1'])
'test 1'
&gt;&gt;&gt; f(['z=p', 'zota', 'g=e', 'yugkb', 'y=t', 'u=o', 'k=s', 'li', 'fg', 'b=='])
'potatoes=life'
&gt;&gt;&gt; f(['p', '=', '==n', 'ot', 'p=a', 'hiz', 'i=e', 'z=r'])
'another'