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Looking at Pseudocode to walk the tangle?, in order to walk the tangle you look at the open tips and then you look for the parents. getTips gives you a list of all the open tips. What API call is needed however to get the parents?

Helmar
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SatoshiReport
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1 Answers1

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The 2 parents of a transactions are called trunk transaction and branch transaction.

You get them like this: (It's python but the names and arguments in other libraries are very similar)

getTips returns a list of transaction hashes

tips = api.get_tips()['hashes']

Call getTrytes to fetch a transaction from its hash. (tips[0] for the first transaction in tips)

transaction_trytes = api.get_trytes([tips[0]])['trytes']

Transaction.from_tryte_string takes the trytes and casts them into a Transaction-object

transaction = Transaction.from_tryte_string(transaction_trytes[0])

To get the parents, use the properties of the transaction

trunkTransactionHash = transaction.trunk_transaction_hash()
branchTransactionHash = transaction.branch_transaction_hash()

Then you can call getTrytes again

trunkTransaction = api.get_trytes([trunkTransactionHash])
Zauz
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  • I've read the documentation about the lazy Tips and why you should use these algorithms in order to get the "best" Tips. But I have a question: is possible to choose by myself what tips refer to? And is possible to refer to a parent transaction that is not a Tip? – Matteo D'Onofrio Oct 10 '22 at 15:58