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0answers
10 views

solidity convertion uint256 and address to string

Is there a way to easily convert uint256 and address types to string so that we can get a human readable value?
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0answers
11 views

Invalid string crashes Remix IDE

If I have an empty function that accepts a string memory input, and if I pass invalid strings like: " "a """ the Remix IDE crashes. Is this just an issue with Remix? If not, ...
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0answers
12 views

Any known hacks by storing string with non-alphanumeric values?

I was checking out hashmasks smart contracts, and they have the following rules for names: No name can be identical There is a limit of 25 symbols (including spaces) Uniqueness is case insensitive (i....
39
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8answers
35k views

How to convert a bytes32 to string

How can I convert a bytes32 to a string? Does anyone has a magic function or library which does it?
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2answers
199 views

How to convert string to bytes256 or arbitrary bytes?

I already know how to convert bytes32ToString and stringToBytes32: function bytes32ToString(bytes32 x) public pure returns (string memory) { bytes memory ...
3
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3answers
1k views

How to handle dynamic size string array in solidity?

I have a shop owner and a shop owner can have multiple products. I want to keep the products id in an array. Also, A public method can return all the product id list of a shop owner. I tried the ...
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0answers
16 views

Solidity: How to represent bytes32 as string

This may be simple in other languages but I can't figure out how to do it in Solidity. I have a bytes32 like this 0x05416460deb76d57af601be17e777b93592d8d4d4a4096c57876a91c84f4a712. I don't want to ...
0
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0answers
25 views

Concatenating strings overwriting a variable

I'm building a SC with many strings and concatenations. Is there any way to overwrite a string and, moreover, not using an auxiliary method? Something like: // SPDX-License-Identifier: MIT pragma ...
0
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1answer
188 views

Empty string in mapping(address => string[])

I have a mapping(address => string[]). How can I check if, given an address and a position of the array string[] corresponding at that address, it exists a value in that position or not? Thank ...
2
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1answer
205 views

Calling a string variable

Update2: Ismael highlighted that upgrading drizzle and Web3 were crucial. I was using drizzle 1.3 and Web3 1.0. So, using the same Solidity code, I can now read a string array into a webpage, using ...
1
vote
1answer
26 views

How to concatenate an address to a string in solidity

I am trying to find the correct way to concatenate an Ethereum address to a string in Solidity v0.6.7 I tried the following but it did not seem to work : function append(string a, address b) ...
1
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0answers
6 views

Check string similarity percentage

How can I efficiently check the similarity of two strings? Or better yet, if I have an array of strings, I want to check that the given string is less than e.g. 80 % similar to any of the other ...
0
votes
1answer
151 views

Convert a string in scientific notation to a number

my smart contract uses an Oracle to retrieve the price. The price is returned as a string in scientific notation, for example, "3e-8". How I can convert this to number (uint)? The token has ...
0
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0answers
33 views

VM error: invalid opcode. invalid opcode The execution might have thrown

I am trying to take in a 512 character long string and extract the first 312 characters from the string. This is my test on a small scale, tryign to extract 12 characters out from a 30 character long ...
0
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2answers
649 views

Events with string argument not working (not indexed)

I am trying to listen to an event on rinkeby test which I run locally. Every thing works fine when my argument is int such as event EventTester(int values); When I change the event argument to string ...
5
votes
3answers
5k views

How can I return dynamic string array in Solidity?

How can I return a dynamic string array? I came across serialization and deserialization. How can I serialize and deserialize dynamic string array ? pragma solidity ^0.5.0; contract Abc{ string[]...
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2answers
16 views

How to ensure that a string parameter to a function is not empty?

Lets say that I have a function which needs two string parameter , function data(string memory _firstname, string memory _lastname) public { buyer[msg.sender] = Buyer(_firstname, _lastname); } Now, I ...
22
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4answers
19k views

Convert address to string

In Solidity, how can I convert the sender address to a string? The comments in How to convert an address to bytes in Solidity? did not provide a working solution
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2answers
81 views

how to set a require for a string to not be null

I want to write a require condition for string that string variable could not be null. How to write because string is not taking the != operator function createOrder(address _seller, string memory ...
1
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1answer
189 views

Can I use an emoji as part of a string in Solidity?

Can I use an emoji in Solidity?
20
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5answers
27k views

Conversion of uint to string

I am trying to convert uint to string in solidity. Is it possible to convert? if so how can I convert it? Convertion to base 10 is prefered, but in hexadecimal might also be helpful.
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0answers
26 views

String to float maintaining decimal places

I've seen some thread already however I haven't found anywhere a way of converting a string number to float number and maintaining the decimals. ie "27.546" to 27.546
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0answers
11 views

How can I generate hash of string received from function argument

I want to generate hash of string received through function argument. Sha256 require bytes in argument. How can I convert and then save hash in _hash variable. struct ORGANIZATION{ bytes32 hash; ...
3
votes
1answer
216 views

In solidity, how to copy a string or pass it by value?

In this example I only modify string a, but both a and b are changed. It seems like the string wasn't copied. I only want to change a. How do you copy a string and how do you pass a string by value to ...
3
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1answer
173 views

What is the maximum size of string which we can store on solidity?

Is there a limit to the size of a string that we can store on the Ethereum blockchain?
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0answers
18 views

How much is the biggest BytesX type in solidity? (Bytes32?)

I'm trying to keep it simple while returning and array of strings. I want to return a fixed bytesX array with small text. How much is the possible X in the BytesX type? In Remix it seems to be Bytes32....
0
votes
1answer
55 views

How do I order strings in Solidity?

I'm a newbie to smart contract development, and I'm looking to order strings using solidity, I don't care that much what kind of ordering method (alphabetical for example) is used, I just want it to ...
0
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0answers
102 views

join an array of strings and map, filter, reduce functions in solidity

I want to concatenate an array of strings into a single string using solidity, just like the array join function in javascript and python. Also I want to do map/filter/reduce functions in an array. Is ...
0
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2answers
683 views

Solidity Split Comma-Delimited String into Individual words

Since Solidity functions can't accept String Arrays as arguments, I'm trying instead to pass in a long comma-delimited string, and then convert it to an array of strings on the fly. I'm close - but ...
0
votes
1answer
279 views

How to concatenate uint to address in solidity?

I would like to concatenate an Ethereum address to an uint in Solidity. How can I do that?
1
vote
1answer
106 views

TypeError: Type string calldata slice is not implicitly convertible to expected type string memory

I want to slice a string and save it to a memory or storage variable. Is this possible? function test(string calldata _input) external{ string memory something = _input[1:3]; } I am ...
3
votes
1answer
4k views

Solidity convert hex string to bytes

I try to convert hex string to bytes. function MyContract() public { string memory str = "A76A95918C39eE40d4a43CFAF19C35050E32E271"; array1 = bytes(str); bytes memory str1 = hex"...
0
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0answers
23 views

Making sure a string (input/output) is less then 64 characters

I'm working though some basic solidity tutorials using remix. I'm having trouble with the concept that there is no way to edit a string built into the language. In other programing languages I would ...
0
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0answers
40 views

Splice an Address

So in javascript I can take a string such as yourString[7] and get the 8th character within that string returned to me in string format. I want to take the last character in an Ethereum address, be an ...
0
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0answers
25 views

Compare strings

I want to compare two strings but, by using: require(keccak256(abi.encodePacked(_car))==keccak256(abi.encodePacked(car))); I get the following error: InternalCompilerError: Unknown ...
14
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6answers
10k views

How to convert string to int

How do i convert a string into a int? here is my code: pragma solidity ^0.4.6; contract MyContract { string public a; /* Constructor */ function MyContract() { a = "0....
0
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0answers
28 views

Passing a hash value to function

I'm trying to authenticate users by comparing the hashes created by backend server and contract. Seems like "byte32" values cannot be coerced into strings. So, instead I'm converting it into ...
0
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1answer
165 views

Explicit type conversion not allowed from “string memory” to “uint256”

I'm using an oracle to get results from a custom api. The result is in string by default. I want to convert it to uint256, so that I can perform basic arithmetic functions. Here's my code: function ...
1
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1answer
78 views

In Solidity, Is there any situation, when string is necessary?

In Solidity, Is there any situation, when string is necessary? Please can u explain when I should use string instead of bytes or bytesN? Thanks!
5
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2answers
3k views

Solidity Invalid implicit conversion from string memory to bytes memory requested

pragma solidity ^0.5 contract ProofOfExistence { // ... some code here function proofFor(string memory document) public view returns(bytes32) { return sha256(document); } //...
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0answers
279 views

How can I return string array in solidity?

This is my struct: struct Token { address tokenAddress; uint256 minAmount; bool emergencyUnlock; TokenStatus status; string name; uint256 decimal; string thumbnailUrl; } ...
0
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0answers
59 views

Gas-efficient string concatenation

My use-case requires that I feed my contract with a long string (Base64 data), which requires to split it and send it over several transactions so as to not reach gas limit. Then the contract rebuilds ...
0
votes
1answer
61 views

Read and write private variable from child contract

I have a contract MyContract is ERC721. MyContract needs to concatenate a string with an existing token URI using this function: string(abi.encodePacked(_tokenURIs[_tokenId], _URI)); Problem is all ...
1
vote
1answer
27 views

How to save long textual data on blockchain? [closed]

I need to write blogs and save them on blockchain. What are efficient possibilities to store such data on blockchain? Thanks for reading the question, already appreciate your time.
36
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4answers
36k views

How to convert a string to bytes32?

How can I convert a string to a bytes32? Does anyone has a magic function or library which does it? For example: This works since as input I gave 32-bits. But it won't work with "> 32-bit" chars. ...
0
votes
1answer
44 views

Where does the length parameter end and the actual string start in an abi encoded string?

Assuming I decided to ABI encode a very long string (for the purpose of this question I just picked an arbitrary 5-paragraph lorem ipsum text generate by https://www.lipsum.com/feed/html) and get out ...
0
votes
1answer
36 views

Why does declaring returns type bytes memory give a compiler error?

If we have the following code: pragma solidity >= 0.5; contract stringsContract { function takesTwo(string memory str, uint idx) public pure returns (bytes memory) { bytes memory ...
1
vote
1answer
56 views

Garbage in string parameters of events

I have an event defined like this: event Created( address indexed target, string indexed name ); I do emit Created(..., _name); // called function with _name = "comment" which gives ...
1
vote
1answer
376 views

Bytes memory as a function parameter increase gas cost

I've a smartcontract compiled with pragma solidity ^0.4.0; version and one function receives a bytes parameters which contain a long string. In these version it doesnt need to set the parameters as "...
0
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1answer
262 views

Solidity. Concatenate and hash two strings

Hi all I need tho sha256 two strings. I am new to solidity. This is what I've got: function addressToString(address _addr) public pure returns(string memory) { bytes32 value = bytes32(uint256(...