pycharm中join的应用

学习python这几天发现jion的两种用法

li = "alexericrain"
v = ["_".join(li)]
print (v)
#第一种输出结果是['a_l_e_x_e_r_i_c_r_a_i_n']
li = ["alex","crain"]
v = ["_".join(li)]
print(v)
#第二种输出结果是['alex_crain']