• # Missions: Convert Stone to the Different Direction and Hints

Hello! We have some good news for you. New missions that will be interesting for you. Also, we have prepared some hints and articles for you. So, let's start:

ðŸ˜ŽNEW MISSIONS:

Changing direction by Doppelok - your task in this mission is to find how many times sorting directions were changed in a list. Be careful and good luck!

```changing_direction([1, 2, 3, 4, 5]) == 0
changing_direction([1, 2, 3, 2, 1]) == 1
changing_direction([1, 2, 2, 1, 2, 2]) == 2```

Convert and Aggregate by freeman_lex - you are given a list of tuples. Each tuple consists of two values: a string and an integer. You need to create and return a dictionary, where keys are string values from input tuples and values are aggregated (summed) integer values from input tuples for each specific key. Have fun!

```conv_aggr([("a", 7), ("b", 8), ("a", 10)]) == {"a": 17, "b": 8}
conv_aggr([]) == {}
conv_aggr([("a", 5), ("a", -5)]) == {}```

The Final Stone - you have a list of stones with different weights. The result of hitting two stones will be a new stone with a weight difference between the two stones. Try this mission, and we will see how good you are at Python! =)

```final_stone([3, 5, 1, 1, 9]) == 1
final_stone([1, 2, 3]) == 0
final_stone([1, 2, 3, 4]) == 0```

ðŸ’¡USEFUL HINTS FOR NEWBIE:

Since we are interested in getting you strong at Python, we have prepared for you some interesting articles and cheat sheets on topics related to the new missions above.

Basics Cheat Sheet - First of all, a cheat sheet about built-in functions and some methods for different types. Even for more experienced users, it can be useful when traveling on the Checkio islands. Also dictionaries and lists have a lot of methods, so we think you will be glad to have your own collection of useful hints. If you don't have such a collection, it is never late to start one!

String methods - this is a cool article that helps you to learn more about string methods and how they work.

String formating - this is a cool article about f-string. F-string has a lot of tricks that can surprise you!

Time to solve some cool missions. See you on CheckiO!ðŸ™Œ

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