TIL: Converting dataframe column to numpy array

python/converting-dataframe-column-to-numpy-array.md

@@ -0,0 +1,20 @@
+This returns a numpy array:
+
+```python
+arr = df["cluster"].to_numpy()
+```
+
+-----
+
+This returns a numpy array of **unique** values:
+
+```python
+unique_arr = df["cluster"].unique()
+```
+
+You can also use numpy to get the unique values, although there are differences between the two methods([`df.unique`](pandas.pydata.org/pandas-docs/stable/reference/api/pandas.unique.html) doesn't sort while [`np.unique`](numpy.org/devdocs/reference/generated/numpy.unique.html) does):
+
+```python
+arr = df["cluster"].to_numpy()
+unique_arr = np.unique(arr)
+```