How can Python get a list from XML such as Unicode to a list?

Question

I have a problem reading XML. I want to get a 2D array. However, when I get the data from the XML, the type of data is Unicode. Hence, I type to use list(). However, the result is not what I want. Could I use another way to get a 2D list?

How can I remove u, \n, \t and get a correct answer? Thank you.

abc.xml

<text>
    <item id="1">
        [[2, 2, 1],
        [1, 0, 0],
        [1, 0, 0]]
    </item>  
</text>

PYTHON:

import  xml.dom.minidom

dom = xml.dom.minidom.parse('abc.xml')

bb = dom.getElementsByTagName('item')
b=bb[0]

l= b.firstChild.data
print l

a=list(l)
print a

The OUTPUT:

[[2, 2, 1]
 [1, 0, 0] 
 [1, 0, 0]]

[u'\n', u' ', u' ', u' ', u' ', u'\t', u'\t', u'[', u'\n', u' ', u' ', u' ', u' ', u'\t', u'\t', u'\t', u'[', u'2', u',', u' ', u'2', u',', u' ', u'1', u']', u'\n', u' ', u' ', u' ', u' ', u'\t', u'\t', u'\t', u'[', u'1', u',', u' ', u'0', u',', u' ', u'0', u']', u' ', u'\n', u' ', u' ', u' ', u' ', u'\t', u'\t', u'\t', u'[', u'1', u',', u' ', u'0', u',', u' ', u'0', u']', u' ', u'\n', u' ', u' ', u' ', u' ', u' ', u' ', u' ', u' ', u' ', u' ', u' ', u' ', u' ', u' ', u' ', u' ', u'\n', u' ', u' ', u' ', u' ', u'\t', u'\t', u']', u'\n', u' ', u' ', u' ', u' ', u'\t']
[Finished in 0.1s]

`eval` should be used with extreme precaution, as it would exceute any code, not just return a list. — MartinStettner, Nov 26 '15 at 15:58

score 1 · Accepted Answer · edited May 23 '17 at 12:16

1

This question is very similar to an old one: Convert string representation of list to list in Python

In short, you want to parse a unicode string (u"[\n[1,2,3],\n...") into an python list literal, so you want to do the same thing the python interpreter does while reading and parsing a program.

You can use the ast module for this:

import ast
a=ast.literal_eval(l)

in your case. Note that this function will evaluate any python literal, so if you simply put "1" in your xml, the result awill be the number 1

See the documentation for ast.literal_evel for more explanation.

edited May 23 '17 at 12:16

Community

1
1

answered Nov 26 '15 at 15:57

MartinStettner

27,323
13
73
104

It shows the new message again.[[2, 2, 1]IndentationError: unexpected indent What should i do? – Martin Tang Nov 26 '15 at 19:49

score 1 · Answer 2 · answered Nov 26 '15 at 16:03

1

A little bit hacky but works for your case:

import ast
from lxml import html

text = """<text>
    <item id="1">
        [
            [2, 2, 1]
            [1, 0, 0] 
            [1, 0, 0] 

        ]
    </item>  
</text>"""

tree = html.fromstring(text)
data = ast.literal_eval(''.join([x.strip() for x in tree.xpath('//text/item[@id="1"]/text()')[0].replace('\n', '').replace(']','],').strip() if x.strip() !=""]).strip())[0]

print type(data)
print data

Output:

<type 'list'>
[[2, 2, 1], [1, 0, 0], [1, 0, 0]]

answered Nov 26 '15 at 16:03

Andrés Pérez-Albela H.

3,783
1
14
27

i try use this way. It shows "IndexError: list index out of range". When i read the data from XML, it has not the tag ( ). What should i change? – Martin Tang Nov 26 '15 at 20:04
@HimYikTang then edit your question and provide a good XML file content sample – Andrés Pérez-Albela H. Nov 26 '15 at 20:14

score 0 · Answer 3 · answered Nov 26 '15 at 20:03

0

You could just use mapping to convert unicode to string:

new_list = map(str, old_list)

answered Nov 26 '15 at 20:03

How can Python get a list from XML such as Unicode to a list?

3 Answers3