One way in "M" would be to use Text.StartsWith like so:
let Source = Csv.Document(File.Contents("C:\temp\powerbi\like.csv"),[Delimiter=",", Columns=2, Encoding=1252, QuoteStyle=QuoteStyle.None]), #"Promoted Headers" = Table.PromoteHeaders(Source), #"Added Custom" = Table.AddColumn(#"Promoted Headers", "Custom", each if Text.StartsWith([column2],"6980") then 1 else 0), Custom = #"Added Custom"{0}[Custom] in Custom
Make sure you column (column2) is Text and then you can filter the resulting column to just 1.