[FIXED] pulling a variable out of a function in a while loop and nested if statement in python

Issue

Hi I am having trouble pulling a variable out of a function and then using it in a mathematical equation. I can use the function usdExRateRand no problem but when try to use the value usdExRate from the function in a nested if statement it only uses the initial usdExRateRand not the newly defined one from the while loop how do i fix this?

import random

def whiles():
    cur1 = "NZD"
    cur2 = "USD"
    usdExRate = round(random.random() * (0.909 - 0.101) + 0.101, 3)
    print ("usdExRate Initial = $", usdExRate)
    nzdExRate = round(random.random() * (1.909 - 1.101) + 1.101, 3)
    print ("nzdExRate Initital = $", nzdExRate)
    amt = 1000
    amt2 = 0
    amtPrev = 0
    amt2Prev = 0

    def usdExRateRand():
        usdExRate = round(random.random() * (0.909 - 0.750) + 0.750, 3)
        print ("USD Ex Rate = $", usdExRate,"\n")
    usdExRateRand()

    def nzdExRateRand():
        nzdExRate = round(random.random() * (1.505 - 1.101) + 1.101, 3)
        print ("NZD Ex Rate = $", nzdExRate, "\n")
    nzdExRateRand()

    while amt > 0:
        def trade1():
    #       usdExRate = round(random.random() * (0.909 - 0.101) + 0.101, 3)
            print ("TRADE 1")
            usdExRateRand()
            if usdExRate > 0:
    #       def trade1():
    #       usdExRate = round(random.random() * (0.909 - 0.101) + 0.101, 3)  
    #       print (usdExRate)
                if (usdExRate * amt > amt2Prev):
                    print ("My Amount to trade =", cur1," $", amt)
                    print ("my ",cur2,"rate = $", usdExRate)
                    trd1 = amt * usdExRate
                    print ("trade1", cur1,"$", amt," * ",cur2,"$",usdExRate," = $", trd1, "\n")
                    amt2 = trd1
                    amtPrev = amt

                else:
                    print ("error reluts in a loss\n")
                    trade1()
        trade1()

        def trade2():
            print ("TRADE 2")
            nzdExRateRand()
            if nzdExRate > 0:
                if (nzdExRate * amt2 > amtPrev):
                    print ("My Amount to trade =", cur2," $",amt2,"\n")
                    print ("my", cur1, "rate = $", nzdExRate)
                    trd2 = amt2 * nzdExRate
                    print ("trade2", cur2,"$", amt2," * ",cur1,"$",nzdExRate," = $", trd2, "\n")
                    amt1 = trd2
                    amt2Prev = amt2
                else:
                    print ("error results in a loss\n")

        trade2()

#            amtPrev = amt
#            def usdExRateom2():
#                usdExRate2 = round(random.random() * (1.909 - 1.101) + 1.101, 3)
#                print ("my nzd rate", usdExRate2)
#            
#            if (trd1 * usdExRate2 < amtPrev):
#                
#                usdExRate2 = round(random.random() * (1.909 - 1.101) + 1.101, 3)
#                
#            else:
#                trd2 = trd1 * usdExRate2
#                print ("trade2 =", trd2)
#            usdExRateom2()  




whiles()

hopefully i got my indentation right this time when copying over the code the code works in spyder and i get this output as you can see after "my amount to trade" the usd ex rate is always 0.3 not the value above.

TRADE 1
USD Ex Rate = $ 0.761 

My Amount to trade = NZD  $ 1000
my  USD rate = $ 0.3
trade1 NZD $ 1000  *  USD $ 0.3  = $ 300.0 

TRADE 2
NZD Ex Rate = $ 1.178 

error results in a loss

TRADE 1
USD Ex Rate = $ 0.772 

My Amount to trade = NZD  $ 1000
my  USD rate = $ 0.3
trade1 NZD $ 1000  *  USD $ 0.3  = $ 300.0 

TRADE 2
NZD Ex Rate = $ 1.296 

what i would like to do is.

def trade():
    usdExRaterand()

this should give me a new usdExRate variable I can then use in the following if statement

Solution

Here's a very vague example that should only demonstrate how you can pass values to your functions and how to return values. I'm not sure what you want to achieve, so please provide more information and I'll update this post.

import random


def usdExRateRand():
    return round(random.random() * (0.909 - 0.750) + 0.750, 3)


def nzdExRateRand():
    return round(random.random() * (1.505 - 1.101) + 1.101, 3)


def trade1(usdExRate, amtPrev):
    if usdExRate * amt > amtPrev:
        # Do your calculations.
    # Then return the updated amt and previous amt. (If you need them.)
    return amt, amtPrev


def trade2(nzdExRate, amtPrev):
    if nzdExRate * amt > amtPrev:
        # Do your calculations.
    # Then return the updated amt and previous amt.
    return amt, amtPrev


def main():
    amt = 1000
    amtPrev = amt

    while amt > 0:
        usdExRate = usdExRateRand()
        nzdExRate = nzdExRateRand()
        print("USD Ex Rate = $", usdExRate)
        print("NZD Ex Rate = $", nzdExRate)
        amt, amtPrev = trade(usdExRate, amtPrev)
        amt, amtPrev = trade2(nzdExRate, amtPrev)


main()

Answered By - skrx