'How to delete particular array in 2 dimensional NumPy array by value?
Let the 2-dimensional array is as below:
In [1]: a = [[1, 2], [3, 4], [5, 6], [1, 2], [7, 8]]
a = np.array(a)
a, type(a)
Out [1]: (array([[1, 2],
[3, 4],
[5, 6],
[1, 2],
[7, 8]]),
numpy.ndarray)
I have tried to do this procedure:
In [2]: a = a[a != [1, 2])
a = np.reshape(a, (int(a.size/2), 2) # I have to do this since on the first line in In [2] change the dimension to 1 [3, 4, 5, 6, 7, 8] (the initial array is 2-dimensional array)
a
Out[2]: array([[3, 4],
[5, 6],
[7, 8]])
My question is, is there any function in NumPy that can directly do that?
Updated Question
Here's the semi-full source code that I've been working on:
from sklearn import datasets
data = datasets.load_iris()
df = pd.DataFrame(data.data, columns=data.feature_names)
df['Target'] = pd.DataFrame(data.target)
bucket = df[df['Target'] == 0]
bucket = bucket.iloc[:,[0,1]].values
lp, rp = leftestRightest(bucket)
bucket = np.array([x for x in bucket if list(x) != lp])
bucket = np.array([x for x in bucket if list(x) != rp])
Notes:
leftestRightest(arg) is a function that returns 2 one-dimensional NumPy arrays of size 2 (which are lp and rp). For instances, lp = [1, 3], rp = [2, 4] and the parameter is 2-dimensional NumPy array
Solution 1:[1]
You're approach is correct, but the mask needs to be single-dimensional:
a[(a != [1, 2]).all(-1)]
Output:
array([[3, 4],
[5, 6],
[7, 8]])
Alternatively, you can collect the elements and infer the dimension with -1:
a[a != [1, 2]].reshape(-1, 2)
Solution 2:[2]
the boolean condition creates a 2D array of True/False. You have to apply and operation across the columns to make sure the match is not a partial match. Consider a row [5,2] in your above array, the script you wrote will add 5 and ignore 2 in the resultant 1D array. It can be done as follows:
a[np.all(a != [1, 2],axis=1)]
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | Kevin |
| Solution 2 | Usman |
