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From: Nathan Hilterbrand <nhilterbrand@gmail.com>
Newsgroups: comp.lang.python
Subject: Re: Problem to read from array
Date: Sat, 21 Nov 2015 10:52:06 -0500
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On 11/21/2015 10:26 AM, BartC wrote:
> On 21/11/2015 10:41, vostrushka@gmail.com wrote:
>> Hi,
>> I have a file with one parameter per line:
>> a1
>> b1
>> c1
>> a2
>> b2
>> c2
>> a3
>> b3
>> c3
>> ...
>> The parameters are lines of characters (not numbers)
>>
>> I need to load it to 2D array for further manipulations.
>> So far I managed to upload this file into 1D array:
>>
>> ParametersRaw = []
>> with open(file1) as fh:
>>      ParametersRaw = fh.readlines()
>> fh.close()
>
> I tried this code based on yours:
>
> with open("input") as fh:
>     lines=fh.readlines()
>
> rows = len(lines)//3
>
> params=[]
> index=0
>
> for row in range(rows):
>     params.append([lines[index],lines[index+1],lines[index+2]])
>     index += 3
>
> for row in range(rows):
>     print (row,":",params[row])
>
> For the exact input you gave, it produced this output:
>
> 0 : ['a1\n', 'b1\n', 'c1\n']
> 1 : ['a2\n', 'b2\n', 'c2\n']
> 2 : ['a3\n', 'b3\n', 'c3\n']
>
> Probably you'd want to get rid of those \n characters. (I don't know 
> how off-hand as I'm not often write in Python.)
>
> The last bit could also be written:
>
> for param in params:
>     print (params)
>
> but I needed the row index.
>
To get rid of the '\n' (lineend) characters:

with open(file1) as fh:
     ParametersRaw = [line.strip() for line in fh.readlines()]

or, more succinctly..

  with open(file1) as fh:
      ParametersRaw = [line.strip() for line in fh]

Comprehensions are your friend.

Nathan