purrr_walk_test.R

l1 <- list(as.list(1:4),
           as.list(11:15))
l2 <- list(list('a.1'=1,'a.2'=2,'a.3'=3,'a.4'=4),
           list('b.1'=1,'b.2'=2,'b.3'=3,'b.4'=4,'b.5'=5))
lapply(l1,names) # should be nulls
lapply(l2,names) # should be 'a.1' ...

# Use copy so as to leave l1 intact
t1 <- l1
for(i in 1:2) {names(t1[[i]]) <- names(l2[[i]])} # this works
lapply(t1,names)
# but...
t1 <- l1 # reset back to original copy
lapply(t1,names) # Just to verify that all are null
purrr::walk(1:2,function(x) names(t1[[x]]) <- l2[[x]]) # this doesn't work
lapply(t1,names) # All Nulls