Transacting Ether

Vyper has special built-in functions to help with transacting ether. The send keyword can be used to send Ether from the contract to a specified Ethereum address.

The contract will also need to be marked as @payable to transact Ether.

EthSenderContract.vy

# pragma version 0.4.0

balances: public(uint256)
recipient_to_balances_mapping: HashMap[address, uint256]

# General function to send Ether
@external
@payable
def send_ether(_recipient: address, _amount: uint256):
    assert _amount > 0, "Amount must be greater than zero"
    send(_recipient, _amount)

# You may also define `_gas` to attach it to the `send` function so state-altering functions can be invoked
@external
@payable
def send_to_other_address(_recipient: address, _amount: uint256, _gas: uint256):
    assert _amount > 0, "Amount must be greater than zero"

    self.recipient_to_balances_mapping[_recipient] = _amount
    self.balances += _amount
    send(_recipient, _amount, gas=_gas)

RecipientContract.vy

# pragma version 0.4.0

interaction_count: public(uint256)

event SendEtherEvent:
    sender: indexed(address)
    amount: uint256

# The attached `_gas` from `send_to_other_address` used to change state
@external
@payable
def __default__():
    self.interaction_count += 1
    log SendEtherEvent(msg.sender, msg.value)

Vyper Differentiators

Transacting Ether on Vyper is straightforward relative to Solidity's use of different keywords like transfer, call and send.

Transacting Ether

Further Reading: