CODEWITHSUNDEEP
pythonlistfilenames
Yarden
Yarden

Reputation: 679

for loops on text files

I'm writing a huge code and one of the little things I need it to do is go over a text file that is divided to different lines. i need it to create a new list of lines every time the line is empty. for example if the text is: (each number is a new line)

1 2 3 4

5 6 3

1 2

it should build 3 different lists: [1,2,3,4], [5,6,3], [1,2]

this is my code so far (just getting started):

    new_list=[]
    my_list=[]
    doc=open(filename, "r")
    for line in doc:
            line=line.rstrip()
            if line !="":
                    new_list.append(line)
    return new_list

Upvotes: 1

Views: 101

Answers (2)

mgilson
mgilson

Reputation: 309929

You could do something like:

[x.split() for x in fileobject if x.strip()]

To get integers, you could use map:

[map(int,x.split()) for x in fileobject if x.strip()]

where fileobject is the object returned by open. This is probably best to do in a context manager:

with open(filename) as fileobject:
     data_list = [map(int,x.split()) for x in fileobject if x.strip()]

Reading some of the comments on the other post, it seems that I also didn't understand your question properly. Here's my stab at correcting it:

with open(filename) as fileobject:
    current = []
    result = [current]
    for line in fileobject:
        if line.strip(): #Non-blank line -- Extend current working list.
            current.extend(map(int,line.split()))
        else:  #blank line -- Start new list to work with
            current = []
            result.append(current)

Now your resulting list should be contained in result.

Upvotes: 2

jackcogdill
jackcogdill

Reputation: 5122

Ok, This should work now:

initial_list, temp_list = [], []
for line in open(filename):
    if line.strip() == '':
        initial_list.append(temp_list)
        temp_list = []
    else: temp_list.append(line.strip())
if len(temp_list) > 0: initial_list.append(temp_list)
final_list = [item for item in initial_list if len(item) > 0]
print final_list

Upvotes: 3

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