Question

我有这样的名单，

a=['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
b=['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
c=['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 1']

这里我试图替换列表中的每个元素＆＃39; a＆＃39;一个接一个地列出了列表元素＆＃39; c＆＃39;。我试过这段代码：

for i in range(len(a)):
    a[i]=c[i]
    print a
    a=['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']

使用此代码我得到正确的输出：

['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 1']

但是当我将最后一个语句（赋值）替换为

时

for i in range(len(a)):
    a[i]=c[i]
    print a
    a=b

列表＆＃39; b＆＃39;也在更新。如何通过直接分配整个列表来实现这一目标。

Answer 1

只需将最后一行替换为：

a=b[:]

Answer 2

您可以在python中尝试copy moduel

from copy import deepcopy
a = deepcopy(b)

Answer 3

真的不确定你问的是什么，但在我看来，你正在努力实现以下目标：

for i in range(len(a)):
    a[i]=c[i] # change only the specified itemnr of list a with the same itemnr of list c.  
    print a # prints (as you've seen and mentioned to be correct: list a with one of its items replaced by an item of list c)
    a[i]=b[i] # Since list a[i] has been set to c[i] earlier in the loop doesn't mean it can't be changed again in the same loop.
    print a

输出：

['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 1']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']

或者，如果您要处理类似于b的列表a，您也可以这样做（因为列表b的长度与a完全相同）：

for i in range(len(a)):
        a[i]=c[i] 
        print a 
        b[i]=c[i]
        print b

输出：

['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 1']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 1']

或者你可以这样做：

for x in [a,b]:
    for i in range(len(x)):
        x[i]=c[i]
        print(x)

输出：

['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 1']
['name test', 'maximum-net-data-rate 4294967295', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 0', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967295', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 0']
['name test', 'maximum-net-data-rate 4294967296', 'minimum-expected-throughput 1', 'maximum-gamma-data-rate 4294967296', 'minimum-gamma-data-rate 1']

列表分配

3 个答案: