Hey, try to find information about starkware here: https://starkware.co/starknet/

_This answer was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

Newton

Where can I learn more about starknet?

What is starknet all about people

_This question was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

Where can I learn more about starknet?

How to verify Empiric’s Data Entries Using Events?

Hi. I am seeing this error in my tests after upgrade.

```
(starknet-py) JediSwap % protostar test tests/test_deployment.cairo 
17:59:05 [INFO] Collected 1 suite, and 3 test cases (0.062 s)                                                                                                    
[UNEXPECTED_EXCEPTION] tests/test_deployment.cairo                                                                                                               
Traceback (most recent call last):
  File "protostar/commands/test/test_runner.py", line 98, in run_test_suite
  File "protostar/commands/test/test_runner.py", line 155, in _build_execution_state
  File "protostar/commands/test/environments/setup_execution_environment.py", line 38, in execute
  File "protostar/starknet/execution_environment.py", line 32, in perform_execute
  File "starkware/starknet/testing/contract.py", line 293, in execute
  File "starkware/starknet/testing/contract.py", line 303, in _execute_on_given_state
  File "protostar/starknet/cheatable_state.py", line 97, in execute_entry_point_raw
  File "starkware/starknet/testing/state.py", line 241, in add_messages_and_events
  File "starkware/starknet/business_logic/execution/objects.py", line 337, in get_sorted_events
IndexError: list assignment index out of range
```

_This question was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

StarkNet error while deploying: IndexError: list assignment index out of range. Can anyone help?

Can you help how to change the code so that it outputs 400 as well?

```
// The following code outputs the numbers 100, 200, 300.
// 1. Click on "Run" to see the output.
// 2. Change it to output 400 as well.

// Use the output builtin.
%builtins output

// Import the serialize_word() function.
from starkware.cairo.common.serialize import serialize_word

func main{output_ptr: felt*}() {
// Output 100 by calling serialize_word.
serialize_word(100);
// Output 200.
serialize_word(200);
// Output 300.
serialize_word(300);
// Return.
return ();
}
```

---

> Answers to this question are a part of the ✨ **17 days of Cairo Lang with Playground & Newton.** ✨ 

*Vote for your favorite answer - the best answer will win a $10 award. A new day – a new reward! During the next 17 days, our goal is to attract more developers to the Cairo language and to systematize the knowledge of Cairo lang. [Read rules](https://www.notion.so/17-days-of-Cairo-Lang-with-Playground-Newton-550dfcda6a2d449ca468be293c776578)*

How to make output like "hello world" in Cairo Language (StarkNet)?

Is there an equivalent of return (true) in cairo on Starknet?


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/686)_

Cairo: How to return true from a function?

Hello! This is day 3 of the 17 days of the Cairo Challenge. And I have no idea how to solve the [playground](https://www.cairo-lang.org/playground/) exercise “Conditionals”. Perhaps you can help me?

```python
// The function `abs_eq` should return 1 if its inputs
// are equal or differ only in sign and 0 otherwise.
// Its current implementation is incorrect.
//
// 1. Click on "Run" to see where it fails.
// 2. Fix the body of `abs_eq`, so that the
//    program terminates successfully.

// Returns 1 if |x| = |y| (that is, x = y or x = -y),
// 0 otherwise.
func abs_eq(x: felt, y: felt) -> (bit: felt) {
    if (x == -y) {
        return (bit=1);
    } else {
        return (bit=0);
    }
}

func main() {
    let (bit) = abs_eq(2, -2);
    assert bit = 1;

    let (bit) = abs_eq(2, 3);
    assert bit = 0;

    let (bit) = abs_eq(2, 2);
    assert bit = 1;

    return ();
}
```

---


> Answers to this question are a part of the ✨ **17 days of Cairo Lang with Playground & Newton.** ✨

*Vote for your favorite answer - the best answer will win a $10 award. A new day – a new reward! During the next 17 days, our goal is to attract more developers to the Cairo language and to systematize the knowledge of Cairo lang. [Read rules](https://www.notion.so/17-days-of-Cairo-Lang-with-Newton-550dfcda6a2d449ca468be293c776578)*

How to make conditional expressions if..then..else in Cairo lang?

Hi. Is there any tutorial for Cairo?


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/334)_

Cairo start.

I have the following code:


`@external`


`func updateCurrNum{syscall_ptr : felt*, pedersen_ptr : HashBuiltin*, range_check_ptr}(updatedNum : felt):`


 `let (isOwner) = isOwner()`


 `assert isOwner = 1`


`...`


And I am getting this error: 


Unexpected '.' after '__main__.updateCurrNum.isOwner' which is future.


 let (isOwner) = isOwner()


 ^*****^


What am I doing wrong?


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/806)_

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