Python - Iterate through list of list strings

Question

I have a list of lists of strings, and I would like to iterate through the 2nd index in each sublist. But, instead of assessing each string it is assessing each character of each string... here is what i mean:

Current Code:

fruit = [['bananna',"apple",'grape'],['ham',"sammy",'canada']]    
for l in range(len(fruit)):  
    for i in fruit[l][1]:    
        print i

Desired output:
apple
sammy

Current output:
a
p
p
l
e
s
a
m
m
y

Really I would like to take some action with each string. Search for that string in another list but right now it appears to be assessing every character of the strings I want to look at instead of the string as a whole... not sure why?

Ahasanul Haque · Accepted Answer · 2016-05-03 16:48:39Z

3

What you are doing:

for l in range(len(fruit)): #you have the inner_loops in each iteration  

    for i in fruit[l][1]: # You already have what you want in fruit[l[1]

        #you are now getting charcter by character from each value

What should do:

Just skip a loop. And it is more pythonic to iterate by value, not by index.

fruit = [['bananna',"apple",'grape'],['ham',"sammy",'canada']]    
for l in fruit:      
        print l[1]

edited May 3, 2016 at 16:48

answered May 3, 2016 at 16:40

Ahasanul Haque

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Comments

Carlos Mermingas · Accepted Answer · 2016-05-03 19:19:35Z

1

Solution:

>>> for l in fruit:
...     print(l[1])
... 
apple
sammy

It works because the for statement allows to iterate over the elements of a list (no index needed).

Original problem:

1 fruit = [['bananna',"apple",'grape'],['ham',"sammy",'canada']]    
2 for l in range(len(fruit)):  
3    for i in fruit[l][1]:    
4        print i

The problem is in line 3:

fruit[l] is one of the sub-lists (e.g. ['banana', 'apple', 'grape']).
fruit[l][1] is the second item in this list ('apple').
for i in fruit[l][1] iterates over the string ('apple'), which picks up each character.

edited May 3, 2016 at 19:19

answered May 3, 2016 at 16:41

Carlos Mermingas

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4 Comments

Carlos Mermingas Over a year ago

Strings are iterable in Python. What's happening is that in for i in fruit[l][1], you are iterating over every character in the second string in every sub-list.

CodeMouse92 Over a year ago

While this code may answer the question, providing additional context regarding why and/or how it answers the question would significantly improve its long-term value. Please edit your answer to add some explanation.

Carlos Mermingas Over a year ago

Thank you for your feedback @JasonMc92

CodeMouse92 Over a year ago

Thank you, @CarlosMermingas, for the edit. Very well done!

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