Efficient Python array with 100 million zeros?

Question

What is an efficient way to initialize and access elements of a large array in Python?

I want to create an array in Python with 100 million entries, unsigned 4-byte

Answer 1

For fast creation, use the array module.

Using the array module is ~5 times faster for creation, but about twice as slow for accessing elements compared to a normal list:

# Create array
python -m timeit -s "from array import array" "a = array('I', '\x00'
 * 100000000)"
10 loops, best of 3: 204 msec per loop

# Access array
python -m timeit -s "from array import array; a = array('I', '\x00'
* 100000000)" "a[4975563]"
10000000 loops, best of 3: 0.0902 usec per loop

# Create list
python -m timeit "a = [0] * 100000000"
10 loops, best of 3: 949 msec per loop

# Access list
python -m timeit  -s "a = [0] * 100000000" "a[4975563]"
10000000 loops, best of 3: 0.0417 usec per loop