Скачать или смотреть How to Handle Invalid Character in String Errors in Solidity

Discover how to solve the `Invalid character in string` issue in Solidity while using special characters and UTF-8 encoding in your smart contracts.
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This video is based on the question https://stackoverflow.com/q/67319365/ asked by the user 'Null isTrue' ( https://stackoverflow.com/u/8577350/ ) and on the answer https://stackoverflow.com/a/67319453/ provided by the user 'Petr Hejda' ( https://stackoverflow.com/u/1693192/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Invalid Character in String Issue in Solidity

Working with smart contracts in Solidity is a rewarding experience, but sometimes developers run into frustrating issues, particularly when it comes to using strings that include special characters. If you're developing an ERC20 Smart Contract and attempting to incorporate text from Latin-based countries, you may have encountered the following error while using Remix, an online development environment for Ethereum:

[[See Video to Reveal this Text or Code Snippet]]

This error typically arises from the presence of special characters like ç and Ã, which is not recognized by the Solidity compiler. If you’re dealing with other special characters, such as é or ô, you need a way to handle them without causing the compiler to throw errors. In this guide, we'll explore how to effectively address this issue by utilizing Unicode encoding.

The Solution: Using UTF-8 Encoding

To include special characters in your strings in Solidity, you can leverage UTF-8 encoding. This allows the compiler to interpret characters that it otherwise wouldn't recognize. Here’s how to go about it.

Step-by-Step Breakdown

Identify Special Characters: First, write down all the special characters you need in your string. This could include:

ç

Ã

é

ô

Convert Characters to UTF-8: For the Solidity compiler to understand these characters, you will need to convert them to their corresponding UTF-8 hexadecimal sequences. Below are common special characters and their UTF-8 representations:

ç = \xC3\xA7

à = \xC3\x83

é = \xC3\xA9

ô = \xC3\xB4

Construct Your String: Using the UTF-8 sequences, you can construct your string variable. For the string "Estado de SÃO PAULO Coçar", it would look like this:

[[See Video to Reveal this Text or Code Snippet]]

Example Code

Here is how your complete Solidity code might appear using the UTF-8 encoding:

[[See Video to Reveal this Text or Code Snippet]]

This converts the special characters correctly and allows you to compile your smart contract without errors.

Conclusion

Utilizing UTF-8 encoding is a straightforward and effective solution to the Invalid character in string error in Solidity. By converting special characters to their UTF-8 hexadecimal sequences, you can include text from languages and regions that use such characters without any hiccups during compilation. This keeps your smart contracts versatile and inclusive of diverse linguistic needs.

Whether you're a seasoned Solidity developer or just starting out, understanding how to manage string encodings can save you time and frustration. Happy coding!