python: how to make list with all lowercase?

Question

Suppose I have some data like:

data[0] = ['I want to make everything lowercase']
data[1] = ['How Do I Do It']
data[2] = ['With A Large DataSet']

How do I repeatedly call the lower() function on all the elements of data, to make all the of strings in lowercase?

I have tried {k.lower(): v for k, v in data.items()}, but I get an error saying that 'list' object has no attribute 'items'.

I have also tried using .lower() and it is giving me the same AtrributeError.

data is not a dictionary,its a list that's why doesnt have items method — Sandeep Lade, Oct 24 '17 at 04:03

score 7 · Accepted Answer · answered Oct 24 '17 at 04:12

7

if your list data like this:

data = ['I want to make everything lowercase', '', '']
data = [k.lower() for k in data]

if your list data is a list of string list:

data = [['I want to make everything lowercase'], ['']]
data = [[k.lower()] for l in data for k in l]

the fact is that list don't has attribute 'items'

answered Oct 24 '17 at 04:12

WIND.Knight

Is the one below the nested for-loops in python? – cohsta Oct 24 '17 at 04:17
1

Yes cohsta. The second solution has nested for loops – Dinesh Pundkar Oct 24 '17 at 04:19

score 5 · Answer 2 · answered Oct 24 '17 at 04:04

5

You need a list comprehension, not a dict comprehension:

lowercase_data = [v.lower() for v in data]

answered Oct 24 '17 at 04:04

Amber

It's still giving me Attribute error saying list object has no attribute lower – cohsta Oct 24 '17 at 04:07
@cohsta - You have list of list data structure. Above solution only works for list data structure. – Dinesh Pundkar Oct 24 '17 at 04:09
@Amber - Requesting you to make your solution working for list of list – Dinesh Pundkar Oct 24 '17 at 04:10
I'm sorry I did not give a sufficient informations. What @DineshPundkar said is correct. – cohsta Oct 24 '17 at 04:15

2 Answers2