how to change column position in pandas code example

Example 1: pandas reorder columns

# setting up a dummy dataframe
raw_data = {'name': ['Willard Morris', 'Al Jennings', 'Omar Mullins', 'Spencer McDaniel'],
        'age': [20, 19, 22, 21],
        'favorite_color': ['blue', 'red', 'yellow', "green"],
        'grade': [88, 92, 95, 70]}
df = pd.DataFrame(raw_data, index = ['Willard Morris', 'Al Jennings', 'Omar Mullins', 'Spencer McDaniel'])
df

#now 'age' will appear at the end of our df
df = df[['favorite_color','grade','name','age']]
df.head()

Example 2: python more order of columns

In [7]: cols = df.columns.tolist()
In [8]: cols
Out[8]: [0L, 1L, 2L, 3L, 4L, 'mean']

In [12]: cols = cols[-1:] + cols[:-1]

In [13]: cols
Out[13]: ['mean', 0L, 1L, 2L, 3L, 4L]
  
In [14]: df = df[cols]

Example 3: pandas reorder columns

# Get column list in ['item1','item2','item3'] format 
df.columns
# [0]output: 
Index(['item1','item2','item3'], dtype='object')

# Copy just the list protion of the output and rearrange the columns 
cols = ['item3','item1','item2']

# Resave dataframe using new column order
df = df[cols]