Python 2.7 NameError: name 'ax1' is not defined

Question

I have Python 2.7 Win 32 and have installed Matplotlib, Numpy, PyParsing, Dateutil. In IDLE I place in the following code:

import matplotlib
import matplotlib.pyplot as plt
import matplotlib.ticker as mticker
import matplotlib.dates as mdates
import numpy as np

def graphRawFX () :
    date=mdates.strpdate2num('%Y%m%d%H%M%S')
    bid, ask = np.loadtxt('GPBUSD1d.txt', unpack=True)
    delimiter=',',
    converters={0:mdates.strpdate2num('%Y%m%d%H%M%S') }
    fig = plt.figure(figsize=(10,7))
    ax1 = plt.subplot2grid((40,40), (0,0), rowspan=40, colspan=40)

    ax1.plot(date,bid)
    ax1.plot(date,ask)

ax1.xaxis.set_major_formatter(mdates.DateFormatter('%Y-%m-%d %H:%M:%S'))

plt.grid(True)
plt.show()

Running the code results in to the following:

Traceback (most recent call last):
  File "C:/Users/Emanuel/Desktop/test.py", line 18, in <module>
    ax1.xaxis.set_major_formatter(mdates.DateFormatter('%Y-%m-%d %H:%M:%S'))
NameError: name 'ax1' is not defined

Any suggestion to editing the code would be helpful.

Answer 1

This is because you are calling ax1 outside the method in which it has been defined it. Perhaps you should include that line in the method as well.

or else:

You can create the ax1 object outside the method and then change some of its attributes as necessary in your function by using global ax1

EDIT: It should look something like this:

import matplotlib
import matplotlib.pyplot as plt
import matplotlib.ticker as mticker
import matplotlib.dates as mdates
import numpy as np


ax1 = plt.subplot2grid((40,40), (0,0), rowspan=40, colspan=40)

def graphRawFX (axes1) :

    date=mdates.strpdate2num('%Y%m%d%H%M%S')
    bid, ask = np.loadtxt('GPBUSD1d.txt', unpack=True)
    delimiter=',',
    converters={0:mdates.strpdate2num('%Y%m%d%H%M%S') }
    fig = plt.figure(figsize=(10,7))

    axes1.plot(date,bid)
    axes1.plot(date,ask)

graphRawFX(ax1)

ax1.xaxis.set_major_formatter(mdates.DateFormatter('%Y-%m-%d %H:%M:%S'))

plt.grid(True)
plt.show()