Adding a string before a nested list using Python

Question

I have a nested list, for example:

names = [['James', 'Logan', 'Timothy'], ['Ander', 'John', 'Henry']]

and before each name, I would like to add this string 'His name is: ' before each name. So it should print, line by line:

His name is: James
His name is: Logan
His name is: Timothy
His name is: Ander
His name is: John
His name is: Henry

I used

for n in names: print(f'His name is: {n}')

but that didn't give me the output I was looking for. Can you please help me figure out how to do this?

Welcome to SO. Please read [How do I ask and answer homework questions?](https://meta.stackoverflow.com/q/334822) - especially the "Make a good faith attempt to solve the problem yourself first." part — Mike Scotty, Sep 27 '21 at 15:39
You'll probably want to look at [Flatten a list of lists](https://stackoverflow.com/q/2158395/5763413), the use of [f-strings](https://realpython.com/python-f-strings/), and [`for` loops](https://wiki.python.org/moin/ForLoop). — blackbrandt, Sep 27 '21 at 15:39
The problem statement is not clear to me. Do you want to actually mutate the list or do you want to prepend that string only during printing/display? — Matias Cicero, Sep 27 '21 at 15:40
I used this at first, but didn't give me what I was looking for: ' for n in names: print(f'His name is: {n}') ' — jarvis, Sep 27 '21 at 15:45
One list, one loop, as in your original question an hour ago… Now you have two nested lists and would need two nested loops… — deceze, Sep 27 '21 at 15:47

Amin · Answer 1 · 2021-09-27T15:50:27.217

2

from itertools import chain


for name in chain.from_iterable(names):
    print(f'His name is: {name}')

edited Sep 27 '21 at 15:50

answered Sep 27 '21 at 15:45

Amin

score 2 · Accepted Answer · answered Sep 27 '21 at 15:49

2

You have a nested list. So, use nested for loop -

names = [['James', 'Logan', 'Timothy'], ['Ander', 'John', 'Henry']]

for i in names:
    for n in i:
        print(f'His name is: {n}')

answered Sep 27 '21 at 15:49

PCM

score 2 · Answer 3 · answered Sep 27 '21 at 15:54

2

If you want to avoid using a nested loop or itertools you can just combine all the nested lists using sum:

names = [['James', 'Logan', 'Timothy'], ['Ander', 'John', 'Henry']]

for name in sum(names, []):
    print(f'His name is: {name}')

answered Sep 27 '21 at 15:54

Jab

3 Answers3