For simplicity, we showed numbers as being stored in-place in the array in the video. However, Python arrays really store pointers to their data, not the data itself (/coding/318 ). The takeaway is the same - there are only two building blocks that make up all data structures - this just means in Python all "edges" are really just pointers! Takeaways Every data structure is made of two building blocks. These building blocks make up every data structure you'll ever come across: Nodes that contain

Theory - Only Two Building Blocks

For simplicity, we showed numbers as being stored in-place in the array in the video. However, Python arrays really store \i{pointers} to their data, not the data itself (\link{/coding/318}).  The takeaway is the same -  there are only two building blocks that make up all data structures - this just means in Python all "edges" are really just pointers!

##Takeaways


Every data structure is made of two building blocks. These building blocks make up every data structure you'll ever come across:

\image{1}

Nodes that contain raw data, like the number 7.

Nodes that tell you where to go to \i{find} other data like on the right. They're  implemented as Arrays or HashMaps, and in Python their edges are always pointers. To see how this works in Python, hover here:  \detail{

In Python:

- Any time you set the value of a variable, like `A = B`, the computer treats the variable `A` as an edge and \i{points} it to item `B` (see \link{/coding/326}).

- Edges must be \i{immutable} or "frozen" (see why in \link{/coding/204, HashMap}).

- You can step along any edge in $O(1)$ time using its key.
}





Data Structures

Theory - Only Two Building Blocks

Takeaways