TypeError：只能串联元组（不能串联“ str”）

Question

我想在我们的设备中自动创建VLAN，但是我的脚本抛出此错误：

 tn.write(cmd + "\\n") TypeError: can only concatenate tuple (not "str") to tuple. 

vlannumbers = int(input("Enter the number for vlans :"))
for i in range(2,vlannumbers):
    cmd = (("/cfg/l2/vlan "), i)

    tn.write(cmd + "\n")
    cmd1 = "apply"
    tn.write(cmd1 + "\n")
    print "ok"
    tn.close()

Answer 1

cmd在代码中保留元组值（不是字符串）。 例如：

>>> cmd = (("/cfg/l2/vlan "), 2)
>>> type(cmd)
<type 'tuple'>   # <--- it's tuple

由于您要将其初始化为字符串，因此您应该执行以下操作：

cmd = "/cfg/l2/vlan {}".format(i)

Answer 2

字符串连接是string类型的对象之间的连接。

您可以尝试以下方法：

vlannumbers = int(input("Enter the number for vlans :"))
cmd_base = "/cdg/l2/vlan"
for i in range(2,vlannumbers):
    # cmd_base is not affected, 
    # since concatenated string value is stored in `cmd`
    cmd = cmd_base + "%d"%i 
    tn.write(cmd + "\n")
    cmd1 = "apply"
    tn.write(cmd1 + "\n")
    print "ok"
    tn.close()