How to replace a element in list of list using python3?

Question

txt =[[""],[""],[""]]
for i in txt:
   x = i.replace("", "apples")
   print(x)

Expected Output:

apples
apples
apples

Possible duplicate of [Replace values in list using Python](https://stackoverflow.com/questions/1540049/replace-values-in-list-using-python) — awesoon, Apr 08 '19 at 06:06
You can just use an answer from the question I have linked and apply it to all elements in your list. — awesoon, Apr 08 '19 at 06:09

score 1 · Answer 1 · answered Apr 08 '19 at 06:09

To replace every instance of "" in the sublists of the main list txt, you can use the following list-comprehension:

txt =[[""],[""],[""]]
txt = [[x if not x=="" else 'apples' for x in sublist] for sublist in txt]

which produces:

[['apples'], ['apples'], ['apples']]

The code you have right now cannot work because given the way you loop over txt, i is the sublist and you python list objects do not have a .replace method.

score 0 · Accepted Answer · answered Apr 08 '19 at 06:11

def replace(value, new_value, outer_list):    
  for inner_list in outer_list:
    for i,element in enumerate(inner_list):
       if element == value:
          inner_list[i]= new_value
  return outer_list
txt =[[""],[""],[""]]
txt = replace("", "apple", txt)

This function could do your need

score 0 · Answer 3 · answered Apr 08 '19 at 06:16

0

Try this one:

txt = [[""],[""],[""]]
for i in range(len(txt)):
    for ii in range(len(txt[i])):
        txt[i][ii] = (txt[i][ii]).replace("","apples")
print(txt)

answered Apr 08 '19 at 06:16

YusufUMS

1,506
1
12
24

DirtyBit · Answer 4 · 2019-04-08T07:02:25.327

0

Using list comprehension:

txt =[[""],[""],[""]]

print([[x if x != "" else 'apples' for x in sub] for sub in txt])

OUTPUT:

[['apples'], ['apples'], ['apples']]

To print them separately;

txt = [[x if x != "" else 'apples' for x in sub] for sub in txt]

for sub in txt:
   for elem in sub:
      print(elem)

OUTPUT:

apples
apples
apples

edited Apr 08 '19 at 07:02

answered Apr 08 '19 at 06:27

DirtyBit

16,613
4
34
55

How to replace a element in list of list using python3?

4 Answers4