Script is fine, but will not run as imported module

Question

With this script/module, XRateDKKUSD_test.py, I can successfully fetch the exchange rate DKK pr USD.

import pandas as pd
import pandas.io.data as web
import datetime

def xRate_pd(years,modus,start=datetime.datetime(2000,1,1),end=pd.Timestamp.utcnow()):
    global xrate, xratedate, df_xrate

    days = int(252 * years)  # ant. arb. dage pr år = 252

    if modus == 'sim':
        start = datetime.datetime(2014,1,1)  # indstil manuelt
        end   = datetime.datetime(2015,5,18) # indstil manuelt

    if modus == 'trading':
        end   = pd.Timestamp.utcnow()
        start = end - days * pd.tseries.offsets.BDay()

    df_xrate = web.DataReader('DEXDNUS', 'fred',
                       start = start, end = end)
    print('df_xrate \n',df_xrate)

    # Selecting only last day from df, saving to xrate, xratedate
    xrate = df_xrate.ix[-1, 'DEXDNUS']
    xratedate = df_xrate.index[-1]

    return xrate, xratedate, df_xrate

if __name__ == '__main__':
#    xrate_lookup()
    xRate_pd(modus='trading',years=0.25)

However, when I try to run this script from my main program with this function...

def xRate(start, end, years, modus): 
    global xrate, xratedate, df_xrate

    xrate, xratedate, df_xrate = XRateDKKUSD_test.xRate_pd(start, end, modus) 

    return xrate, xratedate, df_xrate

Run with this call

import XRateDKKUSD_test
xRate_pd(start, end)

Obviously I have set the 'start' & 'end' parameters in a preceeding function.

when the script is run imported as a module I suddenly run into this problem that I do not get when the script is run stand-alone:

  File "z:/python/crystallball/git - crystalball/_crystalball_main.py", line 277, in <module>
    xRate_pd(start, end)

  File "Z:/python/CrystallBall/Git - CrystalBall/XRateDKKUSD.py", line 55, in xRate_pd
    days = int(252 * years)

TypeError: unsupported operand type(s) for *: 'int' and 'Timestamp'

Anyone who knows why there is this difference, and error when I import and run the script?

Answer 1

Your script has no issues with being imported as a module. You are passing in a different type of object for the years argument.

When you call the code from the if __name__ == '__main__': guard, you pass in years as a float:

xRate_pd(modus='trading', years=0.25)

which works fine for your multiplication:

days = int(252 * years)  # ant. arb. dage pr år = 252

but when you call your function after importing, years is set from the variable start:

xRate_pd(start, end)

and start is not a float but a Timestamp instance, as evidenced by the error message:

TypeError: unsupported operand type(s) for *: 'int' and 'Timestamp'

The int here is the 252 literal.