Python:将字符串转换为cod

Question

如果我有以下词典：

foo = {'bar': {'baz': {'qux': 'gap'} } }

我希望用户能够输入“'bar'、'baz'、'qux'、'dop'”[扩展：“'bar'、'baz'、'qux'、'dop'”]进行转换：

{'qux': 'gap'}

至

{'qux': 'dop'}

我希望通过以下方式将用户输入转换为字典查找语句（不确定确切的术语）：

objectPath = "foo"
objectPathList = commandList[:-1]  # commandList is the user input converted to a list

for i in objectPathList:
    objectPath += "[" + i + "]"

changeTo = commandList[-1]

上面的命令使objectPath=“foo['bar']['baz']['qux']”和changeTo='dop'

太好了！但是，现在我在将该语句转换为代码方面遇到了问题。我原以为eval（）可以做到这一点，但下面的方法似乎行不通：

eval(objectPath) = changeTo

如何转换字符串objectPath以替换硬编写的代码？你知道吗

Answer 1

我会这样做

foo = {'bar': {'baz': {'qux': 'gap'}}}
input = "'bar','baz','qux','dop'"

# Split the input into words and remove the quotes
words = [w.strip("'") for w in input.split(',')]

# Pop the last word (the new value) off of the list
new_val = words.pop()

# Get a reference to the inner dictionary ({'qux': 'gap'})
inner_dict = foo
for key in words[:-1]:
    inner_dict = inner_dict[key]

# assign the new value
inner_dict[words[-1]] = new_val

print("After:", foo)