附加到列表仅附加第一项答案

【问题标题】：Appending to a list only appends first item附加到列表仅附加第一项
【发布时间】：2019-06-13 16:30:39
【问题描述】：

我有一个列表，我试图将数据注入其中。列出一个看起来像这样

data2 = ['TECH2_HELP', 'TECH2_1507', 'TECH2_1189', 'TECH2_4081', 'TECH2_5625', 'TECH2_4598', 'TECH2_1966', 'TECH2_2573', 'TECH2_1800', 'TECH2_1529']

我正在尝试制作的主列表将使用我现有的配置打印出来。下面的打印不是预期的结果，因为您可以看到它只添加了 data2 列表中的第一项。其次，当我尝试使用 for 循环时，我将所有 data2 数据混合在同一个列表中，请参阅 data3。

config1 = ['interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!', 'interface Gi3/0/7', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!', 'interface Gi1/0/11', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!', 'interface Gi3/0/35', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!', 'interface Gi3/0/41', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!', 'interface Gi3/0/25', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!', 'interface Gi3/0/43', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!', 'interface Gi3/0/23', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!', 'interface Gi3/0/19', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!', 'interface Gi3/0/39', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!']

data3=['interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP','description TECH2_1507','description TECH2_1189','description TECH2_4081','description TECH2_5625','description TECH2_4598','description TECH2_1966','description TECH2_2573','description TECH2_1800','description TECH2_1529', '!','interface Gi3/0/7', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP','description TECH2_1507','description TECH2_1189','description TECH2_4081','description TECH2_5625','description TECH2_4598','description TECH2_1966','description TECH2_2573','description TECH2_1800','description TECH2_1529', '!','interface Gi1/0/11', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP','description TECH2_1507','description TECH2_1189','description TECH2_4081','description TECH2_5625','description TECH2_4598','description TECH2_1966','description TECH2_2573','description TECH2_1800','description TECH2_1529', '!','interface Gi3/0/35', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP','description TECH2_1507','description TECH2_1189','description TECH2_4081','description TECH2_5625','description TECH2_4598','description TECH2_1966','description TECH2_2573','description TECH2_1800','description TECH2_1529', '!','interface Gi3/0/41', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP','description TECH2_1507','description TECH2_1189','description TECH2_4081','description TECH2_5625','description TECH2_4598','description TECH2_1966','description TECH2_2573','description TECH2_1800','description TECH2_1529', '!','interface Gi3/0/25', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP','description TECH2_1507','description TECH2_1189','description TECH2_4081','description TECH2_5625','description TECH2_4598','description TECH2_1966','description TECH2_2573','description TECH2_1800','description TECH2_1529', '!',['interface Gi3/0/43', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP','description TECH2_1507','description TECH2_1189','description TECH2_4081','description TECH2_5625','description TECH2_4598','description TECH2_1966','description TECH2_2573','description TECH2_1800','description TECH2_1529', '!','interface Gi3/0/23', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP','description TECH2_1507','description TECH2_1189','description TECH2_4081','description TECH2_5625','description TECH2_4598','description TECH2_1966','description TECH2_2573','description TECH2_1800','description TECH2_1529', '!','interface Gi3/0/19', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP','description TECH2_1507','description TECH2_1189','description TECH2_4081','description TECH2_5625','description TECH2_4598','description TECH2_1966','description TECH2_2573','description TECH2_1800','description TECH2_1529', '!','interface Gi3/0/39', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP','description TECH2_1507','description TECH2_1189','description TECH2_4081','description TECH2_5625','description TECH2_4598','description TECH2_1966','description TECH2_2573','description TECH2_1800','description TECH2_1529', '!',

我尝试在 data2 上将其拆分为 for 和 len，但是当我这样做时，它会将该列表中的所有数据连续放置。

            for line1 in data1:
                words1 = line1.split()
                if len(words1) > 0:
                    local = ''.join(words1[0:1])
                    config1.append('interface ' + local)
                    config1.append('power inline static max 30000')
                    config1.append('spanning-tree portfast')
                    description = ''.join(data2[:1])
                    config1.append('description ' + description)
                    config1.append('!')  # totally optional
                    hostname = None

预期的列表值应如下所示。

expected_config1 = ['interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!', 'interface Gi3/0/7', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_1507', '!', 'interface Gi1/0/11', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_1189', '!', 'interface Gi3/0/35', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_4081', '!', 'interface Gi3/0/41', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_5625', '!', 'interface Gi3/0/25', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_4598', '!', 'interface Gi3/0/43', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_1966', '!', 'interface Gi3/0/23', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_2573', '!', 'interface Gi3/0/19', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_1800', '!', 'interface Gi3/0/39', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_1529', '!']

谢谢

【问题讨论】：

我不太明白你的最终目标是什么——你能澄清一下吗？只需提供输入列表，因为您已经提供了输出列表。
最终目标是将描述合并到 config1 列表中。有问题的输入列表是 data2。
代码中的data1列表是接口列表，即'interface Gi3/0/13'。从上面的 config1 输出中可以看出，该列表已正确附加。
我想我解决了您的问题，但我需要更多信息，因为这可能会改变原本简单的解决方案：data2 是您问题中的字符串列表吗？如果是，则无需像此处description = ''.join(data2[:1]) 那样加入其元素。
Data2 类型是一个字符串列表。但是，我遇到了一个编译问题，如果我不加入，我将无法迭代 str。感谢您的帮助@atru

标签： python list append

【解决方案1】：

问题在于data2 的处理，否则您的整体附加策略是正确的。

首先，您总是只获取data2 的第一个元素。一种解决方案是维护一个单独的计数器（此处为 kdt），每次执行附加阶段时该计数器都会增加，从而跟踪要附加的 data2 元素，

data2 = ['TECH2_HELP', 'TECH2_1507', 'TECH2_1189', 'TECH2_4081', 'TECH2_5625', 'TECH2_4598', 'TECH2_1966', 'TECH2_2573', 'TECH2_1800', 'TECH2_1529']

config1 = []
data1 = ['Gi3/0/13 some more text']*len(data2)

kdt = 0
for line1 in data1:
    words1 = line1.split()
    if len(words1) > 0:
        local = ''.join(words1[0:1])
        config1.append('interface ' + local)
        config1.append('power inline static max 30000')
        config1.append('spanning-tree portfast')
        description = data2[kdt]
        config1.append('description ' + description)
        config1.append('!')  # totally optional
        hostname = None
        kdt += 1

print config1

打印出来：

['interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_HELP', '!', 'interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_1507', '!', 'interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_1189', '!', 'interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_4081', '!', 'interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_5625', '!', 'interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_4598', '!', 'interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_1966', '!', 'interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_2573', '!', 'interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_1800', '!', 'interface Gi3/0/13', 'power inline static max 30000', 'spanning-tree portfast', 'description TECH2_1529', '!']

第二个问题是，通过使用data2[0:1]，您实际上是在创建一个包含一个字符串的列表，即data2 的第一个元素。如果不加入，这将导致尝试在此行中使用+ 连接字符串和列表，

config1.append('description ' + description)

我认为这是您看到的错误。通过按索引访问正确的元素，您实际上是在检索一个字符串，因此不需要连接操作。

【讨论】：