Extracting substrings

Extracting substrings is a crucial component in string manipulation. It means deriving a portion of a string and using it as another column or as part of a transformation logic. Knowing how to extract substrings helps you clean, transform, and organize your data into a more useful format.

In this recipe, we’ll cover how to extract substrings by slicing and regex.

How to do it...

Here’s how you extract substrings from strings in Polars:

1. Use .str.slice() to extract a substring. There are two available parameters in this method: offset and length. The following example only specifies the offset:

    df.select(
       'userName',
       pl.col('userName').str.slice(3).alias('4thCharAndAfter')
   ).head()

   The preceding code will return the following output:

Figure 6.11 – A new column with userName after the 4t character

2. You can specify...