bvowe questions

• Take first non-0 value or last 0 value if that's all there is
• Count unique values by group
• R recode multiple variables following same rules
• R Expand Data Frame List
• Store first non-missing value in a new column
• R Data.Table Multiple Assignment IfElse
• R cummax function with NA
• Summing across rows of a data.table for specific columns with NA
• dplyr: reshape wide to long [duplicate]
• Sample from different data.frame

bvowe answers