Accessing a variable outside a loop Python

Question

I know that the question that i posted has been answered before but i tried to use the posted answers it didn't work well in my case. The problem is that I'm trying to store multiple entries from a while loop into a variable and I'm trying to access this variable outside this loop. The output is only the first line as if the loop is not iterating throw the entire file. Here is the code that I wrote

import csv

keyword = None

with open('test.csv', 'rb') as f:
      reader = csv.reader(f, delimiter='\t')
      headers = reader.next()
      for row in reader:
           keywords = (row[0].strip())

print (keywords)

The test file has the following structure :

symbol
code_id_164751
code_id_313270
code_id_96306
code_id_494305
code_id_468128
code_id_303451
code_id_274562

The output of the code just give me just the first code_id:

code_id_164751

The desired output is the entire list. Even that I declared the variable keywords before the while loop it seems that I could not get it outside the loop (this is what was suggested in the other questions that I saw)

You replace the value of Keywords around every iteration of the loop. — Tony Suffolk 66
– Tony Suffolk 66, Commented Mar 14, 2016 at 14:04
You can get it outside the loop, but keywords is being redefined at each iteration. If it were to build up into a list, it would be a list within your loop as well. Is that really what you want? — zondo
– zondo, Commented Mar 14, 2016 at 14:05
I tried to write it as a list I couldn't get it outside the loop too — Mondher
– Mondher, Commented Mar 14, 2016 at 14:06

Daniel Roseman · Accepted Answer · 2016-03-14 14:08:18Z

3

This has nothing to do with defining the variable inside or outside the loop. You define keyword as a single variable, and re-assign it every time through the loop, so naturally it's only going to get the last value.

Instead you should define it as a list and append your value each time:

keywords = []

...
        keywords.append(row[0].strip())

edited Mar 14, 2016 at 14:08

answered Mar 14, 2016 at 14:05

Daniel Roseman

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3 Comments

gtlambert Over a year ago

You need to pluralise keyword

zondo Over a year ago

@Mondher: Change keyword = [] to keywords = []

Mondher Over a year ago

Thank you I just realised this looking again throw the code.

nathan.medz · Accepted Answer · 2016-03-14 14:06:17Z

0

You need

keywords.append(row[0].strip())

answered Mar 14, 2016 at 14:06

nathan.medz

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Comments

Kapil Rupavatiya · Accepted Answer · 2016-03-14 14:11:51Z

0

Please try to append result to old result. Because in your code you just assign
keywords = (row[0].strip()) so it replace old keyword.

so change keywords = (row[0].strip()) to keywords += (row[0].strip())

answered Mar 14, 2016 at 14:11

Kapil Rupavatiya

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2 Comments

PM 2Ring Over a year ago

Thatprobablywon'tdowhattheOPwants.

Kapil Rupavatiya Over a year ago

Ya but here at this line they also append result to list or append it to simple string.

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