On some Python ah shi

What do variables have to start with?

either a letter or an underscore - can’t start with a number and ARE case sensitive

To make comments (make a code inactive), then…

Add a hash, which is cmd + /

What does % do?

gives remainder of first no. divided by second number

equal to and not equal to

“==” is equal to, “!=” is not equal to

“ifand” function

same as excel, just use “and” with spaces. Same with “or”

“not” used to..

flip a condition you’re checking

Not function example

Print(not(10 < 5 or 13 < 25)) ==> ans is FALSE

If you want to connect two things (like a no. to “sales”), use…

5 = “whatever”

How is a list defined? (what brackets?)

Square brackets [ ]

how would I print the length of my list? (after creating a list, for example [0, 1, 2, 3, 4, 5])

print(len(mylist)

Finding a specific character in your list (remember that indexes and lists start from zero)

print(mylist[2]) - would return 2 if starts from 0

strings vs sequences

strings are also sequences, but can’t be changed once created

How do I return just part of my sequence?

Slice - print(mylist[1 : 4 : 1]) … means print from characters 1 to 4 at a step of 1 character

Trick to reverse sequence

print(mylist[ : : -1])

Tuple

Used to hold data that won’t change (immutable)

How are sets defined? (what brackets)

Curvy brackets! { }

Rules for sets

Can only contain unique values, and repeated numbers won’t print more than once

What does “in” test for?

Tests for membership (whether something is in the list or not)

“in” example

print(1 in mylist) ==> returns TRUE/FALSE

What is the purpose of using mydict

if you do “mydict = {“one” : 1, “two” : 2, 3 : “three”, 4 : “four”}” then you connect pieces of data to “key” values

how to print using mydict

print(mydict[“one”]) returns 1

which values come first and second, values or keys?

Keys first, values second

Can “if” be used in a print statement?

Yes! ==> if x < y : print(“x is less than y”)

How can I created a statement that will return an answer for “if x<y, then say this, but otherwise, say this!”

“x less than y” if (x<y) else “x > or = y”

How do I indent?

Press tab (or insert 4 spaces)

What’s the point of indentation?

indentation is how the computer knows which lines of code belong together