Samir wrote:
On Jul 21, 6:15 pm, Andrew Freeman <[EMAIL PROTECTED]> wrote:
Samir wrote:
On Jul 21, 3:20 pm, Gary Herron <[EMAIL PROTECTED]> wrote:
Samir wrote:
Hi Everyone,
I am relatively new to Python so please forgive me for what seems like
a basic question.
Assume that I have a list, a, composed of nested lists with string
representations of integers, such that
a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
I would like to convert this to a similar list, b, where the values
are represented by integers, such as
b = [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
I have unsuccessfully tried the following code:
n = []
for k in a:
n.append([int(v) for v in k])
print n
Does anyone know what I am doing wrong?
Thanks in advance.
Samir
--
http://mail.python.org/mailman/listinfo/python-list
You didn't tell us how it failed for you, so I can't guess what's wrong.
However, your code works for me:
>>> a = [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
>>> n = []
>>> for k in a:
... n.append([int(v) for v in k])
...
>>> print n
[[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
(Although you seem to have confused variables b and n.)
Gary Herron- Hide quoted text -
- Show quoted text -
Hi Gary,
Thanks for your quick response (and sorry about mixing up b and n).
For some reason, the logic I posted seems to work ok while I'm using
the Python shell, but when used in my code, the program just hangs.
It never outputs the results. Below is the code in its entirety. Is
there a problem with my indendentation?
a = n = []
t = """
1 2
3
4 5 6
7 8 9 0
"""
d = t.split("\n")
for x in range(1,len(d)-1):
a.append(d[x].split(" "))
print a
for k in a:
n.append([int(v) for v in k])
print n
Thanks again.
Samir
--
http://mail.python.org/mailman/listinfo/python-list
I think this will work better, a sub-list comprehension of sorts:
n = [[int(i) for i in k] for k in a]
here is an ipython interactive session using it:
In [1]: a = n = []
In [2]: t = """
...: 1 2
...: 3
...: 4 5 6
...: 7 8 9 0
...: """
In [3]:
In [4]: d = t.split("\n")
In [5]: for x in range(1,len(d)-1):
...: a.append(d[x].split(" "))
...:
...:
In [6]: a
Out[6]: [['1', '2'], ['3'], ['4', '5', '6'], ['7', '8', '9', '0']]
In [7]: n = [[int(i) for i in k] for k in a]
In [8]: n
Out[8]: [[1, 2], [3], [4, 5, 6], [7, 8, 9, 0]]
--
Andrew- Hide quoted text -
- Show quoted text -
Andrew,
Thanks for the tip, though the syntax makes my head spin a bit in
trying to comprehend it. For my small list, I didn't notice a
discernible increase in speed, but I may have to try it with a larger
list size.
Incidentally, I had never heard of iPython but from their web site, it
looks like an interesting tool. I'll have to check it out.
Thanks.
Samir
--
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If it helps look at this:
n = [[int(i) for i in k] for k in a]
like this:
n = []
for k in a:
for i in k:
n.append(int(i))
It is more verbose and easier to read and they both do exactly the same
thing!
iPython is great, to install it you might try easy_install:
http://peak.telecommunity.com/DevCenter/EasyInstall
Then in a command line type:
easy_install ipython
Then, once it is complete, to use iPython type:
ipython
--
Andrew
--
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