# How to replace only 1d values in 2d array after filter using numpy in python

• Hi,
How to replace only 1d values in 2d array after filter using numpy in python without loop i.e in pythonic way.

I want to filter only t2 rows and replace values in second column ( middle column ).

example:

x = np.array([['t1',10,20],['t2',11,22],['t2',12,23], ['t3',21,32]])

x
array([['t1', '10', '20'],
['t2', '11', '22'],
['t2', '12', '23'],
['t3', '21', '32']],
dtype='|S2')

replace_value_for_t2_col1 = [100,101]

## so expected output is

array([['t1', '10', '20'],
['t2', '100', '22'],
['t2', '101', '23'],
['t3', '21', '32']],
dtype='|S2')

## What i tried was,

Filter rows for t2

x[x[:,0]=='t2']

array([['t2', '11', '22'],
['t2', '12', '23']],
dtype='|S2')

x[x[:,0]=='t2'][:,1] = np.array([101,102])

Seems right, but not replacing. i guess it make a copy when we slice using [:,1], so its not changing in same array.

Please suggest me any brilliant ,simple and pythonic ideas, techniques.

• Hi,

You're currently out of the forum scope. You should rather go to a python forum for that question.