mention .str.replace() and to_numeric() for conversion

Author: afeld

assignments.md

@@ -101,8 +101,10 @@ For this course, it's recommended that you try doing the work yourself, asking t
 - **`SettingWithCopyWarning`:** [How to fix](https://www.dataquest.io/blog/settingwithcopywarning/)
 - **`input()` stuck:** Jupyter can be a bit buggy when dealing with interactive input. If it seems to get stuck or you aren't seeing a prompt when you'd expect one, try clicking the `Runtime` menu then `Restart Kernel`.
 - **In a visualization, the values are out of order along the axis, or you're seeing vertical/zig-zag-y lines:** Make sure that:
-  - The values are integers/floats/[timestamps](https://plotly.com/python/line-charts/#line-plots-on-date-axes), not strings, where applicable.
-    - See the [`thousands` argument for `read_csv()`](https://pandas.pydata.org/docs/user_guide/io.html#thousand-separators).
+  - The values are integers/floats/[timestamps](https://plotly.com/python/line-charts/#line-plots-on-date-axes), not strings, where applicable. To convert, see:
+    - The [`thousands` argument for `read_csv()`](https://pandas.pydata.org/docs/user_guide/io.html#thousand-separators)
+    - [`.str.replace()`](https://pandas.pydata.org/docs/reference/api/pandas.Series.str.replace.html)
+    - [`to_numeric()`](https://pandas.pydata.org/docs/reference/api/pandas.to_numeric.html)
   - [Line charts: The column used for the X axis is sorted.](https://plotly.com/python/line-charts/#data-order-in-line-charts)
 - [**`AttributeError: partially initialized module 'orjson' has no attribute 'OPT_NON_STR_KEYS'`:**](https://github.com/plotly/plotly.py/issues/3567) Add the following cell before your other Plotly code, then `Restart session and run all`.