help with python code

**bvdet** · Nov 28 '08, 04:32 PM

Show us the work you have done so far, and we will try to help.

I think the calculation will go something like this:

population += population*(bir th_rate - death_rate)
population += (movein_rate - moveout_rate)

This calculation will need to be done for each year in the difference between the target date and 2004.

I would create a function that returns the projected population.

Code:

def projected_pop(year):
    ....code....
    return calculated_pop

The input could be done something like this:

Code:

print int(projected_pop(int(raw_input("Enter year"))))

**Smygis** · Nov 28 '08, 06:35 PM

its a simple formula.

(BasePopulation + (MoveinRate - MoveoutRate) * year) * year^(BirthRate - DeathRate)

If i remember my math correctly. Something i'm not sure of.

**Kvod10** · Nov 30 '08, 06:41 AM

try using this to start

Code:

def popfunct(year):
    baseyear = 2004
    basepop = 26000
    birthrate = 0.007
    deathrate = 0.006
    movein = 300
    moveout = 325
    
    newpop = #...math...

    return newpop

when you make your GUI use float(int(raw_i nput("whatever you wanna say"))) for the input. I wouldn't just use int; your dealing with a lot of decimals

**Kvod10** · Nov 30 '08, 06:43 AM

here's the function a little clearer

Code:

float(int(raw_input(" Prompt ")))

**bvdet** · Nov 30 '08, 06:03 PM

Originally posted by Kvod10

here's the function a little clearer

Code:

float(int(raw_input(" Prompt ")))

Thanks for posting Kvod10.

Actually, there is no need to convert to float in this case. An integer multiplied or divided by a float will return a float.

I would recommend type casting the appropriate data type. The input is supposed to be a year, therefore the appropriate data type is integer. A population count should be integer also. Since the rates are float, the interim calculation will produce a float which is necessary. The future population should therefore be cast to integer.

**imran akhtar** · Dec 16 '08, 10:38 AM

birthrate code

below i have made the code, but comes up with error
message: TypeError: unsupported operand type(s) for ^: 'int' and 'float'

Code:

(result=(Basepop + (Movein - Moveout) * year) * year^(Birthrate - Deathrate) 
year=input("enter year:")

Birthrate = 0.007
Deathrate = 0.006
Movein = 300
Moveout = 325
Baseyear = 2004
Basepop=26000


result=(Basepop + (Movein - Moveout) * year) * year^(Birthrate - Deathrate)

print "estimated population", (result)

**bvdet** · Dec 16 '08, 03:33 PM

Character "^" is the Python bitwise XOR operator symmetric difference operator for sets. I think you need the power operator "**".

**imran akhtar** · Dec 16 '08, 05:33 PM

how would i power the operrator , is possiable if you could show
thanks

**bvdet** · Dec 16 '08, 05:45 PM

The power operator works like this:

Code:

>>> 2**2
4
>>> 2**0.5
1.4142135623730951
>>>

**imran akhtar** · Dec 17 '08, 05:38 PM

population

sorry, i am confused with power operater, and i have now messed up my code lol, before it worked, after i made changes, it does work, and displays an arror messge such as

(result=(Basepo p + (Movein - Moveout) * year) * year^(Birthrate - Deathrate)
TypeError: unsupported operand type(s) for ^: 'int' and 'float'

i have attched the code in txt file, so you can see problem.

Attached Files

pop.txt (804 Bytes, 512 views)

**bvdet** · Dec 17 '08, 05:45 PM

Replace "^" with "**":

Code:

year**(Birthrate - Deathrate)

-BV

**imran akhtar** · Dec 17 '08, 06:01 PM

thanks it works, very greatful

help with python code

help with python code

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