Helvin wrote:
Hi,
Sorry I did not want to bother the group, but I really do not
understand this seeming trivial problem.
I am reading from a textfile, where each line has 2 values, with
spaces before and between the values.
I would like to read in these values, but of course, I don't want the
whitespaces between them.
I have looked at documentation, and how strings and lists work, but I
cannot understand the behaviour of the following:
line = f.readline()
line = line.lstrip() # take away whitespace at the
beginning of the
readline.
list = line.split(' ') # split the str line into a list
# the list has empty strings in it, so now,
remove these empty strings
for item in list:
if item is ' ':
print 'discard these: ',item
index = list.index(item)
del list[index] # remove this
item from the list
else:
print 'keep this: ',item
The problem is, when my list is : ['44', '', '', '', '', '',
'0.000000000\n']
The output is:
len of list: 7
keep this: 44
discard these:
discard these:
discard these:
So finally the list is: ['44', '', '', '0.000000000\n']
The code above removes all the empty strings in the middle, all except
two. My code seems to miss two of the empty strings.
Would you know why this is occuring?
Regards,
Helvin
(list already is a defined name, so you really should call it something
else.
As Chris says, you're modifying the list while you're iterating through
it, and that's undefined behavior. Why not do the following?
mylist = line.strip().split(' ')
mylist = [item for item in mylist if item]
DaveA
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