address[] twitteruser;

function twitterhandles(address _address,string _twitterhandle)  public  {

    for(uint i=0;i<=twitteruser.length;i++){

        if(twitteruser[i] ==_address)

    handles[_address].twitterhandle = _twitterhandle;

Why is the output is getting thrown? Any help is appreciated. Thanks in advance.

  • Hi there. Are you saying that the condition in the if statement is being met and throw is being called, and you want to know why? Or something else? Oct 11, 2018 at 20:08
  • yes. This is the case .This is just a sample code where I want to iterate through the dynamic array.
    – Kartikey
    Oct 12, 2018 at 5:00

1 Answer 1


As this is coded there are at least two obvious reasons why it might throw.

Setting aside a malformed transaction (possible), the other two are:

  1. The twitter user already exists which is not allowed, because if(twitteruser[i] ==_address) throw;
  2. There are too many twitter users because cost increases with each new twitter user. It will get more expensive to add them. Eventually, it will be impossible to add them at any cost.

for(i=0; i < unlimited; i++) is a well-known anti-pattern.

Hope it helps.

  • this is just a sample code. here I just want to iterate through the dynamic array. but it is giving a throw in its first insertion.
    – Kartikey
    Oct 12, 2018 at 5:03

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