DEV Community: Jay

Sets

Jay — Wed, 21 Oct 2020 01:42:05 +0000

Sets are lists with no duplicate entries.
Since the rest of the sentence uses words which are already in the set, they are not inserted twice.

print(set("I want it Pronto and I am late".split()))

Sets are huge importance. When look for differences and intersections between other sets. For example, say you have a list of participants in events A and B:

a = set(["or", "ni", "car"])
print(a)
b = set(["oui", "non"])
print(b)

To find out which members attended both events, you may use the "intersection" method:

a = set(["or", "ni", "car"])

b = set(["oui", "non"])


print(a.intersection(b))
print(b.intersection(a))

To find out which members attended only one of the events, use the "symmetric_difference" method:

a = set(["or", "ni", "car"])

b = set(["oui", "non"])


print(a.symmetric_difference(b))
print(b.symmetric_difference(a))

To find out which members attended only one event and not the other, use the "difference" method:
To receive a list of all participants, use the "union" method:

a = set(["or", "ni", "car"])
b = set(["oui", "non"])

print(a.union(b))

Break

Jay — Wed, 21 Oct 2020 00:07:37 +0000

break is used to exit a for loop or a while loop, whereas continue is used to skip the current function, and return to the "for" or "while"statement.

e.g:

count = 0
while True:
    print(count)
    count += 3
    if count >= 7:
        break

continue

for x in range(1,20,4):
    # Check if x is even
    if x % 2 == 0:
        continue
    print(x)

range

Jay — Tue, 20 Oct 2020 23:56:28 +0000

The range of a function is domain beginning with x to and end point y.
e.g: P(x,y)

As the term "range" can have different meanings, it is considered a good practice to define it the first time it is used in a textbook or article. Older books, when they use the word "range", tend to use it to mean what is now called the codomain.

Create a sequence of numbers from 2 to 2, but increment by 3 instead of 1:

for n in range(2, 12, 3):
    print(n)

The formula is

for variable in range(start, end, increment) you should
print(variable)

range

Jay — Tue, 20 Oct 2020 22:27:42 +0000

Create a sequence of numbers from 2 to 2, but increment by 3 instead of 1:

for n in range(2, 12, 3):
    print(n)

The formula is

for variable in range(start, end, increment) you should
print(variable)

Control Flow

Jay — Tue, 20 Oct 2020 21:59:30 +0000

Create a simple a list. And let python iterate it.

One quick way of mastering data in the database.

'''
seasons = ['Winter', 'Spring', 'Summer', 'Fall']
for season in seasons:
print(season)

print('In Toronto, we are in' + ': ' + season)
'''

And

Jay — Mon, 19 Oct 2020 23:08:51 +0000

Python has three Boolean operators that are typed out as plain English words: and.
It is on main keyword in python. It is based around Boolean algebra in order of find the truth value of expressions. Depending on the truth value, you can evaluate conditions and decide what operations your programs will execute.
e.g.: (a==true and b==true) is true.
On the other hand, while loops allow you to repeat a piece of code if a given condition remains true.