Learn Pytho

Question 1

List: How to define one?

Answer 1

users[1, 2, “buckle”, “my”, ‘shoe’]

Question 2

List: Difference between forwards, backwards indexing?

Answer 2

Forwards: positive index, start at 0
Backwards, negative index, starts at -1
Backwards counts arrays from the end.

Question 3

List syntax: access n’th element?

Answer 3

users[n-1]

Question 4

List syntax: append element?

Answer 4

users.append(‘item’)

Takes only one argument

Question 5

PCC: Difference between variables and strings?

Answer 5

Variables store numbers, strings store text
1, 2
“high” “low”

Question 6

PCC: What’s a tuple, how is it defined?

Answer 6

(1920, 1080)
Lists where the items can’t be modified.
Uses parentheses instead of square brackets.
() instead of []

Question 7

List: Syntax of list insert?

Answer 7

users.insert(n-1, item)

Inserts item in n’th place, pushing the rest

Question 8

List: Delete by position n

Answer 8

del users(n-1)

Question 9

List: Delete by item

Answer 9

users.remove(item)

Clever. Scans list for item and removes the first item that matches.

Question 10

List: “Pop” or take item n from list

Pop last?

Answer 10

users. pop(n-1)

users. pop()

Question 11

List: find length?

Answer 11

len(users)

Question 12

List: Sort in reverse alphabetical permanently?

Answer 12

users.sort(reverse = True)

Question 13

List: Reverse order?

Answer 13

users.reverse()

Question 14

List: print all items

Answer 14

for user in users:
print(user)

Remember the four spaces.

Question 15

List: slice a list

Answer 15

users(ni:nf)
ni = index of first item
nf = index of last item
blank = take the first (or last) item)

Question 16

Dict: defining one

Answer 16

dict = {key:value, key:value]

Question 17

Dict: accessing a value

Answer 17

dict[‘key’]
OR
dict.get(‘key’)

Question 18

Dict: adding new keys or overwriting old ones

Answer 18

dict[‘key’] = value

Question 19

If: less than/equal to?

Answer 19

<=

less than comes first

Question 20

If: checking presence not in list

Answer 20

“item” not in list

Returns boolean

Question 21

If: Checking for empty lists?

Answer 21

if list

If list is empty, returns false

Question 22

If: exiting an infinite loop?

Answer 22

Ctrl+C

Question 23

Functions: defining one?

Answer 23

def function(input):
    codecodecode

Question 24

Functions: passing keywords

Answer 24

function(in1 = “item”, in2 = “poop”)

Question 25

Functions: specifying default value

Answer 25

def function(in1 = “defaultval”)

Question 26

Functions: specifying optional value

Answer 26

def function(inOpt = None)