Creating a simple forecast

forecast.py

""" 
   This forecast method comes from 
   http://www.sciencecompany.com/-W135.aspx
   input is the current baro (in hPa) and the trend over 3 hours

"""

forecast1_table = \
  (
    (1022, ( (-0.1 , "Continued fair"),
             (-1.55 , "Fair") ,
             (-99 , "Cloudy, Warmer")
           )
    ),
    (1009, ( (-0.1 , "Same as present"), 
             (-1.55 , "Little change"), 
             (-99 , "Precipitation likely")
           ) 
    ),
    (0 , ( (-0.1 , "Clearing, cooler"),
             (-1.55 , "Precipitation"), 
             (-99 , "Storm")
           ) 
    )
)

def find(table,myval) :
    """ lookup up myval in the ordered values in the table. 
 
    Entries in the table are tuples:
       the first value is a float
       the second an obj
    return the first obj whose value is >= myval

    """
    for threshold,value in table :
        if myval >= threshold :
           return value

def forecast1 (baro, trend) :
    return find(find(forecast1_table,baro),trend)

"""
    e.g. print forecast1(1012,2.3)

"""