ismember 1.0.0

Python package ismember returns array elements that are members of set array.

ismember

• Python package ismember returns array elements that are members of set array

Contents

• Installation
• Contribute
• License

Installation

• Install ismember from PyPI (recommended). ismember is compatible with Python 3.6+ and runs on Linux, MacOS X and Windows.
• It is distributed under the MIT license.

pip install ismember

• Alternatively, install ismember from the GitHub source:

git clone https://github.com/erdogant/ismember.git
cd ismember
python setup.py install

Import ismember package

from ismember import ismember

Example:

import numpy as np
from ismember import ismember

# Example with lists
a_vec  = [1,2,3,None]
b_vec  = [4,1,2]
[I,idx] = ismember(a_vec,b_vec)
np.array(a_vec)[I]
np.array(b_vec)[idx]

# Example with DataFrames
a_vec = pd.DataFrame(['aap','None','mies','aap','boom','mies',None,'mies','mies','pies',None])
b_vec = pd.DataFrame([None,'mies','mies','pies',None])
I, idx = ismember(a_vec,b_vec)
a_vec.values[I]
b_vec.values[idx]

a_vec = np.array([1,2,3,None])
b_vec = np.array([1,2,4])
I, idx = ismember(a_vec,b_vec)
a_vec[I]
b_vec[idx]

# Example with Numpy array
a_vec = np.array(['boom','aap','mies','aap'])
b_vec = np.array(['aap','boom','aap'])
I, idx = ismember(a_vec,b_vec)
a_vec[I]
b_vec[idx]

# Example with matrices
# Create two random matrices
a_vec = np.random.randint(0,10,(5,8))
b_vec = np.random.randint(0,10,(5,10))

# Element-wise comparison
Iloc, idx = ismember(a_vec, b_vec, 'elementwise')
# Print results for the first row:
i=0
a_vec[i,Iloc[i]]==b_vec[i,idx[i]]

# Row wise comparison
a_vec = np.array(((1, 2, 3), (4, 5, 6), (7, 8, 9), (10, 11, 12)))
b_vec = np.array(((4, 5, 6), (7, 8, 0)))
Iloc, idx = ismember(a_vec, b_vec, 'rows')
a_vec[Iloc]==b_vec[idx]

print(a_vec[Iloc])
[[4 5 6]]
print(b_vec[idx])
[[4 5 6]]

References

• https://in.mathworks.com/help/matlab/ref/ismember.html

Maintainer

• Erdogan Taskesen, github: erdogant
• Contributions are welcome.
• If you wish to buy me a Coffee for this work, it is very appreciated :)