"?" in M syntax

[JWvanHolst]

Can somebody explain the meaning / function of the "?" in the statement below?

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

[Jimmy801 · Accepted solution]

Hello @JWvanHolst 

is a kinda of error handling. When a column, record or list access isn't existing you normally get an error whereas you get the value null if you add the "?"

Hope that helps

Jimmy

[JWvanHolst]

Thanks. Any reference?

[Jimmy801]

Hello @JWvanHolst 

check out this document link 

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Kudoes are nice too

Have fun

Jimmy