Python replace none in string

I have:

d = [1,'q','3', None, 'temp']

I want to replace None value to 'None' or any string

expected effect:

d = [1,'q','3', 'None', 'temp']

a try replace in string and for loop but I get error:

TypeError: expected a character buffer object

asked Oct 14, 2013 at 15:36

2

Use a simple list comprehension:

['None' if v is None else v for v in d]

Demo:

>>> d = [1,'q','3', None, 'temp']
>>> ['None' if v is None else v for v in d]
[1, 'q', '3', 'None', 'temp']

Note the is None test to match the None singleton.

answered Oct 14, 2013 at 15:36

Martijn Pieters♦Martijn Pieters

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0

You can simply use map and convert all items to strings using the str function:

map[str, d]
#['1', 'q', '3', 'None', 'temp']

If you only want to convert the None values, you can do:

[str[di] if di is None else di for di in d]

answered Oct 14, 2013 at 15:44

0

Starting Python 3.6 you can do it in shorter form:

d = [f'{e}' for e in d]

hope this helps to someone since, I was having this issue just a while ago.

answered Sep 29, 2017 at 12:42

UzzyUzzy

4218 silver badges15 bronze badges

2

Using a lengthy and inefficient however beginner friendly for loop it would look like:

d = [1,'q','3', None, 'temp']
e = []

for i in d:
    if i is None: #if i == None is also valid but slower and not recommended by PEP8
        e.append["None"]
    else:
        e.append[i]

d = e
print d
#[1, 'q', '3', 'None', 'temp']

Only for beginners, @Martins answer is more suitable in means of power and efficiency

answered Oct 14, 2013 at 15:42

K DawGK DawG

12.8k9 gold badges33 silver badges65 bronze badges

4

List comprehension is the right way to go, but in case, for reasons best known to you, you would rather replace it in-place rather than creating a new list [arguing the fact that python list is mutable], an alternate approach is as follows

d = [1,'q','3', None, 'temp', None]
try:
    while True:
        d[d.index[None]] = 'None'
except ValueError:
    pass

>>> d
[1, 'q', '3', 'None', 'temp', 'None']

answered Oct 14, 2013 at 15:43

AbhijitAbhijit

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I did not notice any answer using lambda..

Someone who wants to use lambda....[Look into comments for explanation.]

#INPUT DATA
d =[1,'q','3', None, 'temp']

#LAMBDA TO BE APPLIED
convertItem = lambda i : i or 'None' 

#APPLY LAMBDA
res = [convertItem[i] for i in d]

#PRINT OUT TO TEST
print[res]

answered Jun 29, 2020 at 3:34

Pavan ChandakaPavan Chandaka

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My solution was to match for None and replace it.

def fixlist[l: list]:
    for i, v in enumerate[l]:
        if v is None:
            l[i] = 0

answered Jul 17 at 10:55

0

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