Most answered questions in Blockchain

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Can't install pyethereum module

The module's name is ethereum, not pyethereum. Using the ...READ MORE

Sep 27, 2018 in Blockchain by slayer
 • 29,350 points • 817 views
0 votes
1 answer

How do I compile a piece of Solidity Code using eris' javascript?

The easiest way to compile Solidity is ...READ MORE

Sep 27, 2018 in Blockchain by digger
 • 26,740 points • 650 views
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1 answer

Getting error during “truffle migrate” for an ethereum contract on testrpc

Can you just try to give network ...READ MORE

Sep 27, 2018 in Blockchain by slayer
 • 29,350 points • 471 views
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1 answer

How do I send ether from an EOA to a smart contract?

You include ether to send in the ...READ MORE

Sep 27, 2018 in Blockchain by digger
 • 26,740 points • 1,391 views
+1 vote
1 answer

Deploy contract using solcjs

Try to add some typo and run ...READ MORE

Sep 26, 2018 in Blockchain by slayer
 • 29,350 points • 862 views
+1 vote
1 answer

Calling deployed smart contract from node.js

contractInstance.wakeUp.call is calling the function as constant, but ...READ MORE

Sep 26, 2018 in Blockchain by digger
 • 26,740 points • 3,708 views
+1 vote
1 answer

Solidity: Sending ERC20 Tokens

You can try this code transferTokensTo: function(contract, address_from, ...READ MORE

Sep 26, 2018 in Blockchain by slayer
 • 29,350 points • 1,439 views
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1 answer

Solidity: How can I return a list of user-defined function?

You can do it with something like ...READ MORE

Sep 26, 2018 in Blockchain by digger
 • 26,740 points • 1,153 views
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1 answer

How can I get the same return value as solidity `abi.encodePacked` in Golang?

This is what I used:  package main import ( ...READ MORE

Sep 26, 2018 in Blockchain by slayer
 • 29,350 points • 3,849 views
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1 answer

How connect library to smart contract from external resources?

pragma solidity ^0.4.0; import "github.com/OpenZeppelin/zeppelin-solidity/contracts/math/SafeMath.sol"; contract MathExtended { ...READ MORE

Sep 26, 2018 in Blockchain by digger
 • 26,740 points • 427 views
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1 answer

Is it possible to send eth to a contract through its constructor from another contract?

I found the solution for this: pragma solidity ...READ MORE

Sep 26, 2018 in Blockchain by slayer
 • 29,350 points • 1,523 views
0 votes
1 answer

Testrpc Error: listen EADDRINUSE :::8545 on Mac

Another process is already using the port ...READ MORE

Sep 26, 2018 in Blockchain by digger
 • 26,740 points • 763 views
0 votes
1 answer

Nethereum C# Unit Test GetTransactionCount

You have already made the test async ...READ MORE

Sep 26, 2018 in Blockchain by slayer
 • 29,350 points • 1,252 views
0 votes
1 answer

Error using EtherJS: this.provider.getTransactionCount is not a function

With this line it should work fine: wallet.provider ...READ MORE

Sep 26, 2018 in Blockchain by digger
 • 26,740 points • 2,274 views
+5 votes
1 answer

What are the programming languages I should know to become a Blockchain Developer?

Well, what programming language you have to ...READ MORE

Sep 25, 2018 in Blockchain by digger
 • 26,740 points • 695 views
0 votes
1 answer

Cannot access web3 object with typescript and ethereum

You still need to instantiate it first. ...READ MORE

Sep 25, 2018 in Blockchain by slayer
 • 29,350 points • 2,684 views
0 votes
1 answer

Poloniex C# API - get trades

Outputting the Trade will just show you ...READ MORE

Sep 25, 2018 in Blockchain by digger
 • 26,740 points • 1,215 views
0 votes
1 answer

How to set token price in solidity?

We know that 1 Ether = 1018 wei, ...READ MORE

Sep 25, 2018 in Blockchain by slayer
 • 29,350 points • 8,309 views
0 votes
1 answer

Ethereum call contract method that emits an event, from another contract

You need to refer to the EventEmitter by ...READ MORE

Sep 25, 2018 in Blockchain by digger
 • 26,740 points • 1,888 views
0 votes
1 answer

eth.getTransactionReceipt returns null

It looks like there's an issue with ...READ MORE

Sep 25, 2018 in Blockchain by slayer
 • 29,350 points • 1,910 views
0 votes
1 answer

Call contract methods with web3 from newly created account

In fact, we can't just send transactions ...READ MORE

Sep 25, 2018 in Blockchain by digger
 • 26,740 points • 6,111 views
0 votes
1 answer

Not able send ether to my smart contract's address

It turns out that you need to create ...READ MORE

Sep 25, 2018 in Blockchain by slayer
 • 29,350 points • 1,349 views
0 votes
1 answer

Why Gas Used By Txn is different when invoking the same function in the same smart contract？

The input data might be different, but ...READ MORE

Sep 25, 2018 in Blockchain by Christine
 • 15,790 points • 757 views
0 votes
1 answer

How to detect if an ethereum address is an ERC20 token contract?

There are many possible ways to achieve ...READ MORE

Sep 25, 2018 in Blockchain by Christine
 • 15,790 points • 7,145 views
+2 votes
1 answer

Composer playground - issue on RHEL

Hey, Renu353. There could be more than ...READ MORE

Sep 24, 2018 in Blockchain by Omkar
 • 69,230 points • 912 views
0 votes
1 answer

Getting the length of public array variable (getter)

The calling contract will need the ABI ...READ MORE

Sep 24, 2018 in Blockchain by digger
 • 26,740 points • 1,213 views
0 votes
1 answer

ethminer failed to submit hashrate

The pool you are linking with the -F flag ...READ MORE

Sep 24, 2018 in Blockchain by digger
 • 26,740 points • 808 views
0 votes
1 answer

How to manually create the instance of the contract in truffle?

You can try to do it like ...READ MORE

Sep 24, 2018 in Blockchain by slayer
 • 29,350 points • 2,478 views
0 votes
1 answer

Repeating transactions hangs - web3js, local geth

If you are sending transactions back-to-back from ...READ MORE

Sep 24, 2018 in Blockchain by digger
 • 26,740 points • 881 views
0 votes
1 answer

Not able to send Ethereum transaction

Hey, Change this line: await crowdsale.sendTransaction({value, from: buyer, gas: ...READ MORE

Sep 24, 2018 in Blockchain by slayer
 • 29,350 points • 512 views
+3 votes
1 answer

What is the difference between online and offline hyperledger composer?

Hey @Renu353! Well, it's good that you ...READ MORE

Sep 21, 2018 in Blockchain by Omkar
 • 69,230 points • 691 views
0 votes
1 answer

Can't send transaction even if I use an example from official Ethereum webpage

As I understand your question you are ...READ MORE

Sep 21, 2018 in Blockchain by slayer
 • 29,350 points • 975 views
0 votes
1 answer

Historical ethereum prices - Coinbase API

def get_spot_price(self, **params): """https://developers.coinbase.com/api/v2#get-spot-price""" ...READ MORE

Sep 21, 2018 in Blockchain by digger
 • 26,740 points • 1,687 views
0 votes
1 answer

Test ethereum Event Logs with truffle

You are passing tx hash into done() ...READ MORE

Sep 21, 2018 in Blockchain by slayer
 • 29,350 points • 1,840 views
0 votes
1 answer

Are there null like thing in solidity

You could create none variable to use it as ...READ MORE

Sep 21, 2018 in Blockchain by digger
 • 26,740 points • 1,700 views
0 votes
1 answer

String concatenation in solidity?

A library can be used, for example: import "github.com/Arachnid/solidity-stringutils/strings.sol"; contract C ...READ MORE

Sep 21, 2018 in Blockchain by slayer
 • 29,350 points • 3,178 views
0 votes
1 answer

What do I import for SHA encryption in Node.js?

var sha = require('sha.js'); //... getHash() { ...READ MORE

Sep 21, 2018 in Blockchain by digger
 • 26,740 points • 679 views
0 votes
1 answer

how loop through a JSON Array of bitcoin transaction data

for($i=0; $i<count($result['out']); $i++) { echo ...READ MORE

Sep 21, 2018 in Blockchain by slayer
 • 29,350 points • 555 views
0 votes
1 answer

Syntax Error running on Python

You are missing the closing parenthesis: hashlib.sha256(self.index + ...READ MORE

Sep 21, 2018 in Blockchain by digger
 • 26,740 points • 380 views
0 votes
1 answer

Why do people prefer mining Litecoin over Bitcoin?

The main reason people prefer mining Litecoin ...READ MORE

Sep 21, 2018 in Blockchain by slayer
 • 29,350 points • 516 views
0 votes
1 answer

How to Query hdfs with Spark Sql

Yyou can achieve this by creating Dataframe. val ...READ MORE

Sep 20, 2018 in Blockchain by slayer
 • 29,350 points • 1,892 views
0 votes
1 answer

How to send JSON object from npm module to browser

A simple solution for this would be ...READ MORE

Sep 20, 2018 in Blockchain by digger
 • 26,740 points • 532 views
0 votes
1 answer

Blockchain ToBTC API not returning Php variable

Seems like you have a syntax error ...READ MORE

Sep 20, 2018 in Blockchain by digger
 • 26,740 points • 447 views
0 votes
1 answer

XMLHttpRequest is not defined while sending request to blockchain service via C#

use post data in url link and ...READ MORE

Sep 20, 2018 in Blockchain by slayer
 • 29,350 points • 1,039 views
+2 votes
1 answer

Has Blockchain made illegal activities easier?

Not really.. The transparency of Blockchain makes ...READ MORE

Sep 20, 2018 in Blockchain by Sumit
 • 324 views
+2 votes
1 answer

What is Bitcoin Powered Electrical Outlet?

Bitcoin powered electrical outlet is nothing but ...READ MORE

Sep 20, 2018 in Blockchain by Bhaskar
 • 544 views
+1 vote
1 answer

Ethereum vs Hyperledger: Which is better for business networks?

Hyperledger is preferred for B2B business and ...READ MORE

Sep 20, 2018 in Blockchain by digger
 • 26,740 points • 529 views
+1 vote
1 answer

Can't instantiate any chaincodes on peers of newly Added org

Seems like chaincode install may have been unsuccessful. Before ...READ MORE

Sep 20, 2018 in Blockchain by Perry
 • 17,100 points • 1,889 views
0 votes
1 answer

How to extend Composer rest Server ?

 It looks like you want to query ...READ MORE

Sep 20, 2018 in Blockchain by Perry
 • 17,100 points • 661 views
0 votes
1 answer

How to create an asset on Bigchaindb server using http call

You could start like this: method = POST URL ...READ MORE

Sep 19, 2018 in Blockchain by Christine
 • 15,790 points • 1,160 views
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