I have a bit of a weird question here.
I am using iperf to test performance between a device and a server. I get the results of this test over SSH, which I then want to parse into values using a parser that has already been made. However, there are several lines at the top of the results (which I read into an object of lines) that I don't want to go into the parser. I know exactly how many lines I need to remove from the top each time though. Is there any way to drop specific entries out of a list? Something like this in psuedo-python
print list
["line1","line2","line3","line4"]
list = list.drop([0 - 1])
print list
["line3","line4"]
If anyone knows anything I could use I would really appreciate you helping me out. The only thing I can think of is writing a loop to iterate through and make a new list only putting in what I need. Anyway, thanlks!
Michael
This is what the slice operator is for:
>>> before = [1,2,3,4]
>>> after = before[2:]
>>> print after
[3, 4]
In this instance, before[2:]
says 'give me the elements of the list before
, starting at element 2 and all the way until the end.'
(also -- don't use reserved words like list
or dict
as variable names -- doing that can lead to confusing bugs)
You can use slices for that:
>>> l = ["line1","line2","line3","line4"] # don't use "list" as variable name, it's a built-in.
>>> print l[2:] # to discard items up to some point, specify a starting index and no stop point.
['line3', 'line4']
>>> print l[:1] + l[3:] # to drop items "in the middle", join two slices.
['line1', 'line4']
Slices:
l = ["line1","line2","line3","line4"]
print l[2:] # print from 2nd element (including) onwards
["line3","line4"]
Slices syntax is [from(included):to(excluded):step]
. Each part is optional. So you can write [:]
to get the whole list (or any iterable for that matter -- string
and tuple
as an example from the built-ins). You can also use negative indexes, so [:-2]
means from beginning to the second last element. You can also step backwards, [::-1]
means get all, but in reversed order.
Also, don't use list
as a variable name. It overrides the built-in list class.
why not use a basic list slice? something like:
list = list[3:] #everything from the 3 position to the end
你想要那个
del list[:2]
You can use "del" statment to remove specific entries :
del(list[0]) # remove entry 0
del(list[0:2]) # remove entries 0 and 1
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