import numpy as np

labels = np.array(["api", "web", "api", "batch", "web", "api"])

unique, first_index, inverse, counts = np.unique(
    labels,
    return_index=True,
    return_inverse=True,
    return_counts=True,
)
first_seen_order = np.argsort(first_index)

print("input:", labels)
print("unique sorted:", unique)
print("counts:", counts)
print("first positions:", first_index)
print("first-seen unique:", unique[first_seen_order])
print("first-seen counts:", counts[first_seen_order])
print("inverse:", inverse)
print("reconstructed:", unique[inverse])
print("matches input:", np.array_equal(unique[inverse], labels))