Can I access data in Nx3 Matrix for other column with specific value

Question

Say I have

data=np.array([[30,0.109,1],
               [25,0.517,2],
               [22,0.174,1],
               [35,0.812,3],
               [45,0.215,4],
               [40,0.111,4],
               [50,0.095,4]])

Doing

A = data1[:,2]
print(A)

Will give me

[1. 2. 1. 3. 4. 4. 4.]

Is there a command so I can get the values from other columns (1 or 2) if column 3 has a value of 4 In my mind it would look like this B=data[:,1,[2]=4] So B should print out [0.812, 0.215, 0.111]

Is this possible? The reason I need it is for graphical display. The number in column 3 corresponds to a type of bacteria (I.e. all 4's are the same bacteria), from which I need to plot the other values "bound" to that type of bacteria.

Hope its possible, and all the best

Unfortunately not for me, it prints out exactly the same as print(data[[:, [0,1]]) — Progso224, Jun 12 '23 at 16:37
Does this answer your question? [Numpy select rows based on condition](https://stackoverflow.com/questions/58079075/numpy-select-rows-based-on-condition) — jared, Jun 12 '23 at 16:46

score 0 · Accepted Answer · answered Jun 12 '23 at 16:45

0

You need to use boolean indexing:

out = data[data[:, 2]==4, 1]

Output:

array([0.215, 0.111, 0.095])

answered Jun 12 '23 at 16:45

mozway

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Can I access data in Nx3 Matrix for other column with specific value

1 Answers1