从列表中删除双引号

Question

I'm using sage, python and CSV.

Here is an example row from my csv file:

"(4, 4)",0.921,1.512,1.718,"[[(0, 0, 1), (1, 0, 0)]]","[[(0, 0, 3), (1, 0, 0)]]"

I also have:

with open('log.csv', 'rt') as logFile:
    logreader = csv.reader(logFile)
    for row in logreader:
        a = row[3]
        b = row[4]

I was expecting csv.reader to strip the double-quotes when assigning a and b such that:

a == [[(0, 0.5, 1), (1, 0, 0)]]
b == [[(0, 0, 3), (1, 0, 0)]]

however

a == "[[(0, 0, 1), (1, 0, 0)]]"
b == "[[(0, 0, 3), (1, 0, 0)]]"

What is the best way to achieve what I was expecting? Thanks

Answer 1

You need to use ast.literal_eval to parse the strings into lists:

from ast import literal_eval
with open('log.csv', 'rt') as logFile:
    logreader = csv.reader(logFile)
    for row in logreader:
        a = literal_eval(row[3])
        b = literal_eval(row[4])

See a demonstration below:

>>> from ast import literal_eval
>>> literal_eval("[[(0, 0, 1), (1, 0, 0)]]")
[[(0, 0, 1), (1, 0, 0)]]
>>> type(literal_eval("[[(0, 0, 1), (1, 0, 0)]]"))
<class 'list'>
>>>

Answer 2

I would use the built-in strip function:

a = row[3].strip('"')
b = row[4].strip('"')