how to change column location in pandas code example

Example 1: 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 2: pandas reorder columns by name

#old df columns
df.columns
Index(['A', 'B', 'C', 'D'],dtype='***')
#new column format that we want to rearange
new_col = ['D','C','B','A'] #list of column name in order that we want

df = df[new_col]
df.columns
Index(['D', 'C', 'B', 'A'],dtype='***')
#new column order