title: ValueError: x is required to have ndim 1 but has ndim 2 | ARIMA model and plot_pacf
body: <p>I loaded in data of Bitcoin and tried to plot it into a PACF graph. But it returned this error (<code>x</code> is my dataframe variable):</p>
  
  <pre><code>ValueError: x is required to have ndim 1 but has ndim 2
  </code></pre>
  
  <p>I also get this error when I attempt to fit the model with <code>x</code>. The only way around it is to only give it one column (<code>x.Close</code>). But I want to train the model with all the features. How do I do that?</p>
  
  <p>Full Code:</p>
  
  <pre><code>import pandas as pd
  import numpy as np
  import matplotlib.pyplot as plt
  from pandas.plotting import autocorrelation_plot as acf_plot
  from statsmodels.graphics.tsaplots import plot_pacf
  from statsmodels.tsa.arima_model import ARIMA
  import datetime
  
  x = pd.read_csv('BTC-USD.csv', header=0, parse_dates=['Date'], index_col=0)
  x.index = pd.DatetimeIndex(x.index).to_period('D')
  x = x.sort_index()
  
  """
  plot_pacf(x)
  plt.show()
  """
  
  
  model = ARIMA(x, order=(12, 0, 0))
  model_fit = model.fit()
  print(model_fit.summary())
  
  output = model_fit.forecast()
  
  print(output[0])
  </code></pre>