Why we need line 9 and " " at end of line 11?

Question

1. Phone = input("Phone: ")
2. digits_mapping = {
3. "1": "one",
4. "2": "two",
5. "3": "three",
6. "4": "four"
7. }
8.
9. output = ""
10. for character in phone:
11. output += digits_mapping.get(character, "!") + " "
12. print(output)

Hi,
This is piece code that if we give number, it basically convert it to word,
Can anyone explain what is the reason of line 9 and that " " at the end of line 11?

Answer 1

In line 9 => declared a variable having empty string .

In line 11 => adding values of the dictionary in every iteration using += .

Final value of
output = "one two three four"

Answer 2

Hi Tori ,

line 9:
output = ""
We are declaring a string variable output.
How we know it's string type?
By looking at the data stored in variable output. That is "" for string.

line 11:
+ " ";
we are separating our output by space.
eg: one two three four

I hope this helps!
Ping me if you still have doubts!

Answer 3

Tori we are putting empty string("") because we want our variable output to be of string type.
Just like you put 0 for integers, 0.0 for float or true/false for boolean type.

Answer 4

Read this, you will be clear about static vs dynamic type checking.

https://docs.oracle.com/cd/E57471_01/bigData.100/extensions_bdd/src/cext_transform_typing.html#:~:text=There%20are%20two%20main%20differences,type%20checking%20at%20compile%20time.

Answer 5

Hey Md Sayed,
I know that line 9 is a variable with a empty string but why though?
Why we should put that in there?