如何将类似数据的数组从字符串转换为二维数组？

Question

I am loading the data from an xml file with a structure like:

<project name = "xxx">
    <Parameter name = "yyy">
        <data> <![CDATA[{ { 1, 1, 1, 1}, { 2, 2, 2, 2}, { 3, 3, 3, 3} }]]></data>
    </Parameter>
</project>

I am able to find the data and extract it from xml, but it's in string form along with all the brackets

data = "{ { 1, 1, 1, 1}, { 2, 2, 2, 2}, { 3, 3, 3, 3} }"

I would like to convert it to a 2d array of numbers. At this point I use a code that looks like this:

data2d = data.replace('{','[')
data2d = data2d.replace('}',']')
exec('a = np.array('+ data2d +')')

From that code I get what I want:

a = [[1, 1, 1, 1],[2, 2, 2, 2],[3, 3, 3, 3]]

But I was wondering is there a better way to do that. I really don't like the exec() approach. Does anyone have any other idea?

Answer 1

You can use ast.literal_eval :

from ast import literal_eval

data = "{ { 1, 1, 1, 1}, { 2, 2, 2, 2}, { 3, 3, 3, 3} }"

lst = literal_eval(data.replace("{", "[").replace("}", "]"))

print(lst, type(lst))
# [[1, 1, 1, 1], [2, 2, 2, 2], [3, 3, 3, 3]] <class 'list'>