So far, we have primarily used arrays when we already knew what values should go into them. If you just need to create a new empty array, please use the command np$.$array$([]).$ If you need to add a value, say $4\mathrm{.}2,$ into an array used the command np$.$append$($ array, value$).$ Here is an example:

import numpy as np

Lvalues$=$np$.$array$([])$ #Here is an empty array called Lvalues where we can store the lengths of our pendulums

Lvalues$=$np$.$append$($Lvalues$,4\mathrm{.}2)$ #This command will add a new value, $4\mathrm{.}2,$ into the array

Lvalues$=$np$.$append$($Lvalues$,7\mathrm{.}3)$

print$($Lvalues$)$

Lvalues$=$np$.$delete$($Lvalues$,-1)$ #this command will remove an entry. Negative entries count from the end of the array, positive entries count from the beginning.

Lvalues$=$np$.$delete$($Lvalues$,0)$

What is Lvalues at the end of this block of code?