On 4/20/2013 1:09 PM, Jason Friedman wrote:
I have a file such as:
$ cat my_data
Starting a new group
a
b
c
Starting a new group
1
2
3
4
Starting a new group
X
Y
Z
Starting a new group
I am wanting a list of lists:
['a', 'b', 'c']
['1', '2', '3', '4']
['X', 'Y', 'Z']
[]
I wrote this:
------------------------------------
#!/usr/bin/python3
from itertools import groupby
def get_lines_from_file(file_name):
with open(file_name) as reader:
for line in reader.readlines():
yield(line.strip())
counter = 0
def key_func(x):
if x.startswith("Starting a new group"):
global counter
counter += 1
return counter
for key, group in groupby(get_lines_from_file("my_data"), key_func):
print(list(group)[1:])
------------------------------------
I get the output I desire, but I'm wondering if there is a solution
without the global counter.
def separate_on(lines, separator):
group = None
for line in lines:
if line.strip() == separator:
if group is not None:
yield group
group = []
else:
assert group is not None # Should have gotten a separator first
group.append(line)
yield group
with open("my_data") as my_data:
for group in separate_on(my_data, "Starting a new group"):
print group
The handling of the first separator line feels delicate to me, but this
provides the output you want.
--Ned.
--
http://mail.python.org/mailman/listinfo/python-list
