import numpy as np

y = []
# simulate appending 1130 labels
for i in range(1130):
    y.append(i % 5)

y = np.array(y)
unique_labels = sorted(list(np.unique(y)))
label_map = {lbl: i for i, lbl in enumerate(unique_labels)}
y_mapped = np.array([label_map[l] for l in y])

print(len(y), len(y_mapped))