chars <- c("A", "B", "C", "D")
contain_a <- "A" %in% chars
# contain_a = TRUE
contain_e <- "E" %in% chars
# contain_e = FALSE
# Many at once: one answer for each item
contain_each <- c("A", "E") %in% chars
# contain_each = TRUE FALSE
# Superset: every item of chars2 is in chars
chars2 <- c("A", "B")
contain_all <- all(chars2 %in% chars)
# contain_all = TRUE
cat("contain_a =", contain_a, "\n")
cat("contain_e =", contain_e, "\n")
cat("contain_each =", contain_each, "\n")
cat("contain_all =", contain_all, "\n")