F-String¶

String Formating techniques¶

% - formatting => 1.0v
str.formate() => 2.6 Best for Dictionary
f-string => 3.6 Higly recommened because of concise code, readabilty,speed

timeit module¶

python inbulit module
By using timeit module, we can measure execution tiome of small coding snippets

t = timeit.timeit(code,numbeeer =1000)

numbers =1000 => execute ccode with number 10000 of times PVM take hwo much time it will retuen in sec

example¶

import timeit
t= timeit.timeit('print("hello")',number=1000)
print(f'The time taken {t} sec')

Handling quotes in f-sting¶

subject ='math'
a = 'a'
print(f''' The class of {subject} by "{a}" too good''')

Processing dictionary data by f-string¶

performance wise f-string is grater Higly recommended to use f-string

How to define multi line f-string¶

name = "ashish"
age = 26

message = f'''
    name: {name},
    age: {age}
    '''
print(message)

Python f-string calling a function¶

we can call function directly from f-string

print(f'Name: {name.upper()}')
def mymax(a,b):
    max = a if a>b else b
    return max

a = input("a ")
b = input("b ")

print(f'The max of {a} and {b} is {mymax(a,b)}')
help(__repr__)

__repr__ => String to Object __str__ => Object to string

Python f-string for objects¶

str.format() method will always call str() method only.
but in f-string, we can call either str() or repr() based on our requirment

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def __repr__(self):
        return f"Person(name={self.name}, age={self.age})"

    def __str__(self):
        return f"{self.name}, {self.age} years old"

# Creating an instance of the Person class

person = Person("John", 30)

# Using f-string with __repr__()

print(f"Representation of person: {person!r}")

# Using f-string with __str__()

print(f"String representation of person: {person}")

The repr() method returns a string representation suitable for debugging and development. It is often used with !r in f-strings to call repr() explicitly.

The str() method returns a more user-friendly string representation. When using f-strings, the default string conversion is the same as calling str()

We can use = symbol f-string for self documentating expressions and it is useful for debugging purposes.

x = 10
y = 10
print(f'{x = }')  # => print(f'x = {x}')
print(f'{y = }')  # => print(f'y = {y}')

We can also use walrus operator (:=) inside f-string:

import math
half_radious = 10

print(f'The Area of circle with radius {(r := 2 * half_radious)} is {math.pi ** r*r }')

# *__Note:__* `()` -> This is important in walrous operator in this example other wise we will get error.

print(f'The Area of circle with radius {r := 2 * half_radious} is {math.pi ** r*r }')

f - string can in python 3.6 version but = and := operator are allowed inside f-string in python 3.8 version
% -> formating and str.formate() Not Recommanded. f string

has performance
concise
less verbose
more readable

class Student:
    def __init__(self, name, rollno, marks):
        self.name = name
        self.rollno = rollno
        self.marks = marks
    def __str__(self):
        return f'Name: {self.name}, RollNo: {self.rollno}, Marks: {self.marks}'

    def __repr__(self):
        return f'Student Name: {self.name}, Student RollNo: {self.rollno}, Student Marks: {self.marks}'

s = Student('ashish',101,80)
print('Information-------> {}'.format(s))
print(f'Information-------> {s}')
print(f'Information-------> {s!r}')

Expression inside f-string¶

We can pass expression inside f-string and those expressions will be evaluated at runtime {8*8} print({8*8})

How to use curly braces inside f-string¶

{ => replacement operator
{{=> it is simple of '{'

print(f'{{ is special symbol ')

print(f'{{{ is special symbol ')
n=1000000000
print(f'{n:_}')
n=1000000000
print(f'{n:,}')
n=1000000000
print(f'{n:-}')
n: int = 1_000_000_000
print(n)
n: float = 1e9
print(n)
var: str = 'var'

print(f'{var: > 20}:')
print(f'{var: < 20}:')
var: str = 'var'

print(f'{var:>20}:')
print(f'{var:<20}:')
print(f'{var:20}:')
print(f'{var:^20}:')

# fill element

var: str = 'var'

print(f'{var:_>20}:')
print(f'{var:#<20}:')
print(f'{var:|^20}:')
print(f'{var:*^20}:')

from datetime import datetime

now: datetime = datetime.now()

print(f'{now:%d.%m.%y (%H:%M:%S)}')
print(f'{now:%c}') #local date and time
print(f'{now:%I%p}') #12 p.m
n: float = 1234.5678
print(round(n, 2))
n: float = 1234.5678

print(f'Result: {n:.2f}')
print(f'Result: {n:.0f}')

print(f'Result: {n:,.3f}')
print(f'Result: {n:_.3f}')

a: int = 5
b: int = 10

my_var: str = "ashish"

print(f'{a + b = }')

import string

print(string.ascii_letters)
print(string.digits)
print(string.punctuation)
print(string.printable)

#### Sort below string

file_paths = [
    'static\\pdf\\01 Adsolut initiatie\\page_1.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_10.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_11.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_12.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_13.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_14.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_15.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_16.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_17.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_18.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_19.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_2.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_20.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_21.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_22.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_23.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_24.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_25.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_26.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_27.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_28.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_29.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_3.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_30.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_4.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_5.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_6.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_7.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_8.pdf',
    'static\\pdf\\01 Adsolut initiatie\\page_9.pdf'
]

from faker import Faker
fake = Faker()

help(fake.phone_number)
faker.providers.phone_number()