循环为不同的字符串组合

Question

我在

下面有一个字符串列表

for_vector <- c("a","b","c","d","e","f","g","h","i","j")

我想生成一个循环，它将打印上述字符串的所有可能组合。蜇伤的组合应该是1到10，如下所示

a
b
c
.
.
j
.
.
a+b
a+c
.
.
a+b+c....+j