Python Function is not performing properly with a Global Variable defined

Question

Here is my Function.........

from instrument import Instrument
import pandas as pd

  def getpairsData():
    global pairlist    <<============= Defined Global variable
    pairlist = Instrument.get_pairs_from_list() <<=============Call
    return pairlist   <<============= Available Global variable

"""It is being called by this loop....... #This loop will iterate over pairlist, and will pass one pair to get data, and save that data as file."""

 for pair in pairlist:      <<======= My Global variable above????

    getData()
    for i in range(0,11):
        df1= pd.read_csv("./data/"+ str(files[i])+".csv")
        print (df1.head())



import pandas as pd
import Utils

class Instrument():
def __init__(self,ob):
    self.name=ob['name']
    self.type=ob['type']
    self.displayName = ob['displayName']
    self.pipLocation = pow(10,ob['pipLocation']) # ex. - --> 0.0001
    self.marginRate = ob['marginRate']


@classmethod
def get_pairs_from_list(cls):  <<============= Receive Call 1
    i_list = cls.get_instruments_list()
    i_keys = [x.name for x in i_list]

    df = pd.DataFrame(i_keys)
    df = df.rename(columns={0: "Names"})

    df['Names'] = df['Names'].str.replace("_", '')
    print("You are here")

    pairlist = df["Names"].tolist()  # if it is being changed to a list with no keys

    return pairlist   <<============= Return Call 1

"""I am thinking the pairlist would return to the original function that is set as a Global variable and off to the races we go, but I am stuck on the print("You are here") not responding at all.

NameError: name 'pairlist' is not defined"""

It would also help to post the full traceback message. Is the error at for pair in pairlist: ? Is that for loop in a function? Have you called getpairsData() before you get to this loop? It looks like you haven't called getpairsdata to set the variable. — tdelaney
– tdelaney, Commented Aug 2, 2021 at 22:25
Thanks, I understand your point, but I do think the calls are in the script. I will attempt to place a pointer like <<=============== To Highlight the locations for the call. Thanks for any feedback. — Davis Rogers
– Davis Rogers, Commented Aug 2, 2021 at 22:44
Please reconsider the updated code for your feedback, Thanks again. — Davis Rogers
– Davis Rogers, Commented Aug 2, 2021 at 22:49
I am realizing that its not just a variable, but a Dataframe. Would that cause it not to work properly? — Davis Rogers
– Davis Rogers, Commented Aug 2, 2021 at 22:50

Sabil · Accepted Answer · 2021-08-02 23:34:01Z

As I don't have the full view of your implementation but I think your code should be something like below snippet:

from instrument import Instrument
import pandas as pd

def getpairsData():
  global pairlist
  pairlist = Instrument.get_pairs_from_list() # <<=============Call
  return pairlist   # <<============= Available Global variable
 
pairlist = getpairsData()
 
for pair in pairlist:      # <<======= My Global variable above????
  for i in range(0,11):
    df1= pd.read_csv("./data/"+ str(files[i])+".csv")
    print (df1.head())



import pandas as pd
import Utils

class Instrument():

  def __init__(self,ob):
      self.name=ob['name']
      self.type=ob['type']
      self.displayName = ob['displayName']
      self.pipLocation = pow(10,ob['pipLocation']) # ex. - --> 0.0001
      self.marginRate = ob['marginRate']


  @classmethod
  def get_pairs_from_list(cls):  # <<============= Receive Call 1
      i_list = cls.get_instruments_list()
      i_keys = [x.name for x in i_list]

      df = pd.DataFrame(i_keys)
      df = df.rename(columns={0: "Names"})

      df['Names'] = df['Names'].str.replace("_", '')
      print("You are here")

      pairlist = df["Names"].tolist()  # if it is being changed to a list with no keys

      return pairlist   # <<============= Return Call 1

Davis Rogers · Accepted Answer · 2021-08-02 23:05:12Z

1

"""I have found that  @tdelaney explanation was correct.  I never called 
the variable because it was derived and then needed to be returned."""

@classmethod
def get_pairs_from_list(cls):  <<============= Receive Call 1
    i_list = cls.get_instruments_list()
    i_keys = [x.name for x in i_list]

    df = pd.DataFrame(i_keys)
    df = df.rename(columns={0: "Names"})

    df['Names'] = df['Names'].str.replace("_", '')
    print("You are here")

    pairlist = df["Names"].tolist()  # if it is being changed to a list 
                                    with no keys

    `return getpairsData(pairlist)`   <<=========== Return Call with 
    Variable

answered Aug 2, 2021 at 23:05

Davis Rogers

617 bronze badges

1 Comment

Davis Rogers Over a year ago

I have a pulse now, but something still isn't correct. I will take this off of the radar. Thanks for all of your help..

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