Working in Jupyter Notebooks has some quirks

how to clear output

Sometimes things get really messy and you want to clear the output from a cell or a bunch of cells.

select the cells you want to clear the outpu from and go to this menu:

Cell --> Current Outputs --> Clear

or you can clear all of the output cells:

Cell --> All Output --> Clear

or you can restart the kernel and clear all of the output cells:

Kernel --> Restart & Clear Output

running cells in order

The notebook runs cells in the order that you run them. I can hear you saying Duh! but they are necessarily in linear order, but we can edit them and run them in any order we please. This is both a cool feature and a curse.

run the next few cells of code in order:

my output the first time is:

now run the cell below:

now go back up and run the two cells right before you recorded your output for the first time:

notice the numbers in the Out [ ]: after the the code you just reran -- the number is different!
And so is your output!

my output the second time is:

Remember -- this is both a cool feature and a curse.

I find that if things go super-duper sideways, that restarting and running all the cells helps since this runs them all in linear/sequential order.

you can restart the kernel and run all of the notebook:

Kernel --> Restart & Run All

multiple function calls in one cell

Another quirk is that each code cell can only have one output (one In[ ]:, one Out[ ]:)

to illustrate, assign these 2 variables

by running a code cell with the name, the value is sent to Out[ ]:

see the difference when you call the print() function and pass it the identifier?

again...

it gets worse when you have multiple things in a cell.

The output of a code cell can only be one thing! In this case we only see the output of the last thing in the Out[ ]:

but you can print multiple things...

notice that this one doesn't have an Out[ ]: since we used print.

this will get you at some point, so watch out for it!