CODEWITHSUNDEEP
python
jace8615
jace8615

Reputation: 25

Python - NameError

I have the following code that uses 3 strings 'us dollars','euro', '02-11-2014', and a number to calculate the exchange rate for that given date. I modified the code to pass those arguments but I get an error when I try to call it with

python currencyManager.py "us dollars" "euro" 100 "02-11-2014"

Traceback (most recent call last):
  File "currencyManager.py", line 37. in <module>
    currencyManager(currTo,currFrom,currAmount,currDate)
NameError: name 'currTo' is not defined

I'm fairly new to Python so my knowledge is limited. Any help would be greatly appreciated. Thanks. Also the version of Python I'm using is 3.4.2.

import urllib.request
import re

def currencyManager(currTo,currFrom,currAmount,currDate):    
    try:
        currency_to =  currTo #'us dollars'
        currency_from = currFrom #'euro'
        currency_from_amount = currAmount
        on_date = currDate # Day-Month-Year

        currency_from = currency_from.replace(' ', '+')
        currency_to = currency_to.replace(' ', '+')

        url = 'http://www.wolframalpha.com/input/?i=' + str(currency_from_amount) + '+' + str(currency_from) + '+to+' + str(currency_to) + '+on+' + str(on_date)
        req = urllib.request.Request(url)

        output = ''
        urllib.request.urlopen(req)

        page_fetch =  urllib.request.urlopen(req)
        output = page_fetch.read().decode('utf-8')

        search = '<area shape="rect.*href="\/input\/\?i=(.*?)\+.*?&lk=1'
        result = re.findall(r'' + search, output, re.S)

        if len(result) > 0:
            amount = float(result[0])
            print(str(amount))
        else:
            print('No match found')
    except URLError as e:
            print(e)
currencyManager(currTo,currFrom,currAmount,currDate)

Upvotes: 1

Views: 146

Answers (1)

unutbu
unutbu

Reputation: 880997

The command line 

python currencyManager.py "us dollars" "euro" 100 "02-11-2014"

does not automatically assign "us dollars" "euro" 100 "02-11-2014" to currTo,currFrom,currAmount,currDate. Instead the command line arguments are stored in a list, sys.argv. You need to parse sys.argv and/or pass its values on to the call to currencyManager:

For example, change

currencyManager(currTo,currFrom,currAmount,currDate)

to 

import sys
currencyManager(*sys.argv[1:5])

The first element in sys.argv is the script name. Thus sys.argv[1:5] consists of the next 4 arguments after the script name (assuming 4 arguments were entered on the command line.) You may want to check that the right number of arguments are passed on the command line and that they are of the right type. The argparse module can help you here.

The * in *sys.argv[1:5] unpacks the list sys.argv[1:5] and passes the items in the list as arguments to the function currencyManager.

Upvotes: 4

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