Pandas extract error: "Columns must be same length as key"

Question

Im using Pandas to extract a sub-string from a column in a excel sheet The regex has been tested multiple ways and does work Error below:

Says its found a match but get the same error over and over again

Whats happening

Answer 1

You are probably capturing more than 1 group and all of those are returning another column. You can't assign multiple columns into a single column. Capture a single group with your regex or concatenate your result to your original dataframe. Don't assign it to a single column