2. Loop and Flow Control

Question 1

Control flow

Answer 1

if:
elif:
else:

Question 2

syntax of a for loop

Answer 2

my_interable = [1,2,3]

for xxx in my_iterable:
print( xxx)

Question 3

tuple unpacking

Answer 3

Duplicate the structure in the iterables
For (a,b) in my_tuples:
print(b)

Also mean breaking up a tuple into variable
name, hours = tuple(‘Mary’,100)

Question 4

tuple unpacking in dictionary

Answer 4

by default dictionary loop through the key only

For key,value in d.items():
print(value)

Question 5

while loop

Answer 5

while boolean_condition:
#do something
else:
#do something diff

Question 6

control flow in loop (3 methods)

Answer 6

break: stop the loop
continue: stop and go back to first line
pass: do nothing

Question 7

enumerate function

Answer 7

Zip a count with the iterable object and return a tuple

word = ‘abcde’

for item in enumerate(word):
print(item)

Question 8

combine two list together

Answer 8

for item in zip(mylist1, mylist2):
print(item)

return tuples

Question 9

list comprehension

Answer 9

quick way to replace for loop along with .append()

mylist = [x for x in 'word']
mylist = [x**2 for x in range(1,11) ]
mylist = [x for x in range(1,11) if x % 2 == 0

Question 10

looping through a string (or list)

Answer 10

for i in range(len(text))

Question 11

for/while:

else:

Answer 11

else will be run at the end when the loop is done or while condition is no longer true; break will break the whole loop and break the else as well

Question 12

1) if x:
2) if not x
3) if x is not None

Answer 12

1) if x, means if it is something (i.e. not none or not empty), do something
2) if not x, means do something if none/empty

3) similar to 1 but empty != None anymore
see if x is really not None