1, how to use a custom function in the filter method to filter the data?
. 2, why do I use the series filter (like='dd'), get the index in line with 'dd' content, this logic is a little mess, if I want to filter the contents of the value, how to do?
3, regular type filter method: do not include the so-and-so content how to write? Multiple skewer regular type with a plus sign?
4, this method compared with the if cycle, efficiency has increased? Or just the code concise?
Thank you very much!!