boolean indexing that can produce a view to a large pandas dataframe?

Question

Got a large dataframe that I want to take slices of (according to multiple boolean criteria), and then modify the entries in those slices in order to change the original datafra

Answer 1

Building off of unutbu's example you could also use the boolean index on df.index like so:

In [11]: df.ix[df.index[idx]] = 999

In [12]: df
Out[12]:
      A    B    C
0     9   23   -6
1   999  999  999
2     9   25   -4
3   999  999  999
4     9   27   -2
5   999  999  999
6     9   29    0
7    10   30    1
8     9   31    2
9    10   32    3
10    9   33    4
11   10   34    5