Can't create lists of lists

Question

I am trying to create a list of lists. I have the following lists.

['0.2', '0.1', '0.4', '0.9', '1.0', '1.1', '1.2']
['2.7', '3.2', '2.9', '3.8', '2.9', '2.9', '2.9']
['6.7', '6.4', '4.7', '4.5', '4.7', '5.1', '5.1']
['0.3', '0.4', '0.7', '1.7', '1.8', '2.0', '2.0']
['5.0', '5.1', '5.7', '5.7', '5.6', '5.4', '5.3']

Each row above I have stored in a list object called values. However when I try to run:

for ele in doc.items():
    y0 = ele.attr('y0')
    p = pdf.pq('LTTextLineHorizontal')
    x = 0
    values.clear()
    for elem in p.items():
        if elem.attr("y0") == y0:
            x = x + 1
            if x > 1:
                values.append(elem.text())
    print(values)
    table.append(values)
for value in table:
    print(value)

When I run the last two lines of code I get the following out:

['5.0', '5.1', '5.7', '5.7', '5.6', '5.4', '5.3']
['5.0', '5.1', '5.7', '5.7', '5.6', '5.4', '5.3']
['5.0', '5.1', '5.7', '5.7', '5.6', '5.4', '5.3']
['5.0', '5.1', '5.7', '5.7', '5.6', '5.4', '5.3']
['5.0', '5.1', '5.7', '5.7', '5.6', '5.4', '5.3']

Why is the output not the same as the list of values at the top very top I posted?

Any help would be appreciated Thanks.

you should look up list comprehensions – Craicerjack May 05 '16 at 13:47 — Craicerjack, May 05 '16 at 13:47

score 3 · Accepted Answer · answered May 05 '16 at 13:51

3

table.append(values) appends a reference/pointer to the address of values, so new changes to the values list object will be reflected in all elements of table.
You can do something like table.append(values[:]) to appends a copy of the values object instead.

answered May 05 '16 at 13:51

Phu Ngo

866
11
21

Thanks this worked. Is `table.append(values[:])` the same as `table.append(values.copy())` ? – Chinwobble May 06 '16 at 13:06
Hi! Refer to [this answer](http://stackoverflow.com/a/2612815/1400623) for a more comprehensive look. – Phu Ngo May 12 '16 at 10:28

Can't create lists of lists

1 Answers1