Python: Interpolation
You already know how to move a string or glue several strings together to get a new expression. But there are alternatives to these operations in programming. They make the code more readable and easier to maintain.
The basic way to join strings is concatenation. Using concatenation, the strings are added to each other, as in the example below:
first_name = 'Joffrey'
greeting = 'Hello'
print(greeting + ", " + first_name + "!")
# => Hello, Joffrey!
Concatenation works simply, but doesn't always look so visually clear. The quotation marks make it difficult to see what the end result will be. And the more complex the string is, the more confusing it will start to look. Concatenation has an alternative: interpolation. This is what it looks like:
first_name = 'Joffrey'
greeting = 'Hello'
print(f'{greeting}, {first_name}!')
# => Hello, Joffrey!
The letter f indicates that we are creating an f-string, a pattern into which the value of variables is substituted with the help of curly brackets. The output is a normal string.
Consider this example:
school = 'Hexlet'
what_is_it = f'{school} - online courses'
print(what_is_it) # => Hexlet - online courses
In almost all languages, interpolation is preferable to concatenation for combining strings. This produces strings that are stuck together, and spaces and characters are visible inside it.
Interpolation helps make code clearer to developers. But that's not the only useful alternative we want to talk about. Later in the course, we'll look at how to declare a multiline string without using \n.
Instructions
Print the string, Do you want to eat, <name>? Where the variable starkshould be used instead of
Do you want to eat, Arya?
Definitions
- Interpolation
- a method for obtaining a complex string from several simple ones using special templates
The exercise doesn't pass checking. What to do? 😶
If you've reached a deadlock it's time to ask your question in the «Discussions». How ask a question correctly:
- Be sure to attach the test output, without it it's almost impossible to figure out what went wrong, even if you show your code. It's complicated for developers to execute code in their heads, but having a mistake before their eyes most probably will be helpful.
In my environment the code works, but not here 🤨
Tests are designed so that they test the solution in different ways and against different data. Often the solution works with one kind of input data but doesn't work with others. Check the «Tests» tab to figure this out, you can find hints at the error output.
My code is different from the teacher's one 🤔
It's fine. 🙆 One task in programming can be solved in many different ways. If your code passed all tests, it complies with the task conditions.
In some rare cases, the solution may be adjusted to the tests, but this can be seen immediately.
I've read the lessons but nothing is clear 🙄
It's hard to make educational materials that will suit everyone. We do our best but there is always something to improve. If you see a material that is not clear to you, describe the problem in “Discussions”. It will be great if you'll write unclear points in the question form. Usually, we need a few days for corrections.
By the way, you can participate in courses improvement. There is a link below to the lessons course code which you can edit right in your browser.
languages.lessons.show.chat.disabled
Your exercise will be checked with these tests:
1from hexlet.test import expect_output
2
3
4def test(capsys):
5 expected = 'Do you want to eat, Arya?'
6 expect_output(capsys, expected)
7Teacher's solution will be available in:
