Arrays

Arrays can be defined with a fixed size at compile time, or they can be dynamically sized.

Fixed size arrays are declared by specifying size k in data type T. This is written as T[k].

# pragma version 0.4.0

# Define array with fixed size
fixed_array: uint256[5]

@external
def setFixedArray():
    self.fixed_array = [1,2,3,4,5]

@external
@view
def getFixedArray() -> uint256[5]:
    return self.fixed_array

ℹ️ Note

Avoid defining an array with size larger than 2**64 as this can result in security vulnerabilities due to risk of overflow.

Dynamic arrays length can be modified at runtime, up to a bound specified in the type declaration. This is written as dynArrayVariable: DynArray[T, k].

# pragma version 0.4.0

# Notice you will need to define the size of the dynamic array using `DynArray` keyword
dynamicArrayList: DynArray[uint256, 5]

@deploy
def __init__():
    self.dynamicArrayList.append(100)
    self.dynamicArrayList.append(200)
    self.dynamicArrayList.append(300)
    self.dynamicArrayList.append(400)
    self.dynamicArrayList.append(500)
    # In this example, appending more than 5 elements would revert

@external
@view
def getDynamicArray() -> uint256[5]:
    return self.dynamicArrayList

Vyper Differentiators

Requires explicit specification of size of arrays at compile time.
This applies to both fixed and dynamic array.

Arrays

Further Reading: