title: Editing row of one dataframe appears to affect another? Pandas Python
body: <p>Having a bit of a strange issue, where I must be making some sort of mistake.</p>
  
  <p>My script is as follows: Create one dataframe of 4 rows and 3 columns, full of random values. Then create a second dataframe which is equal to the first one, and then in the second df, change the values of the second row.</p>
  
  <pre><code>import pandas as pd
  import numpy as np
  
  #Create random df
  df1 = pd.DataFrame(np.random.rand(4,3))
  
  #Create a second df which is the same as df1
  df2 = df1
  
  #Viewing them both, the look the same
  df1
  df2
  
  #Now edit row #1 of df2
  df2.iloc[1:2] = [[0 , 0, 1]]
  
  #Now viewing them both, both df1 and df2 have row #1 as 0, 0, 1
  </code></pre>
  
  <p>I thought that df2 = df1 would be a one time assignment and the two dataframes would be entirely separate from then on?</p>