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Python: Syntactic Sugar

Constructions like index = index + 1 are often found in Python, so the creators of the language added an abbreviated version: index += 1.

The only difference is how they're written. The interpreter will turn an abbreviated construction into its expanded form.

These abbreviations are called syntactic sugar because they make the process of writing code a little easier and more pleasant.

There are abbreviated forms for all arithmetic operations and for string concatenation:

  • a = a + 1a += 1
  • a = a - 1a -= 1
  • a = a * 2a *= 2
  • a = a / 1a /= 1


Implement a function called filter_string() that takes a string and a character as input, and returns a new string with the character removed from every point in the string. Try not to use the built-in methods for working with the string in your solution.

text = 'If I look back I am lost'
filter_string(text, 'I')  # 'f  look back  am lost'
filter_string(text, 'o')  # 'If I lk back I am lst'
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.

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