operator ?

[CCCP]

Hi , looking at the operation made by power bi when importing a folder with csv files i have found this step

where this formula is written

= Table.SelectRows(Source, each [Attributes]?[Hidden]? <> true)

what is this ? ,where i can find the meaning of this sintax?

thanks

[CCCP]

thanks you sir

[AlienSx · Accepted solution]

Hi, @CCCP  

it's M operator optional-field-selector:  [ field-name ] ?

Nice nick BTW! CCCP forever!