df$1=$ pd$.$DataFrame$(\{"$key$"$: $["$b$","$b$","$a$","$c$","$a$","$a$","$b$"],$

"data$1"$: pd$.$Series$($range$(7),$ dtype$=$"Int$64")\})$

df$1$

df$2=$ pd$.$DataFrame$(\{"$key$"$: $["$a$","$b$","$d$"],$

"data$2"$: pd$.$Series$($range$(3),$ dtype$=$"Int$64")\})$

df$2$

join df$1$ and df$2$ use "merge"function

apply outer join of df$1$ and df$2$

apply right join of df$1$ and df$2$

apply left join of df$1$ and df$2$

appy inner join of df$1$ and df$2$