Penerapan Data Mining untuk Prediksi Penjualan Produk Skincare Menggunakan Metode KNN (K-Nearest Neighbors): Studi Kasus Klinik Ayume Beauty Care Authors Putri Yulia Amanda Universias Bhayangkara Surabaya Berlian Aisya Damayanti Universias Bhayangkara Surabaya Alisya Akbar Choirun Universias Bhayangkara Surabaya Selvi Novita Sari Universias Bhayangkara Surabaya Siti Armiyanti Universias Bhayangkara Surabaya M. Mahaputra Hidayat Universias Bhayangkara Surabaya DOI: https://doi.org/10.69688/dike.v3i1.122 Keywords: Sistem Informasi, Analisis sentiment, K-Nearest Neighbors, Pra-Pemrosesan Data, CountVectorizer, TF-IDF