print("Hello world")

Hello world

Define variables in python

# define a variable to store number
number = 10
print(number)

10

# define a variable to store string value
name = "John Smith"
print(name)

John Smith

# concatenate variables and display values
print("Hello " + name + ", the number is " + str(number))

Hello John Smith, the number is 10

print("Hello")
print("World")

Hello
World

tv = 15
mobile = 20
tablet = 30

# use \ to indicate codes continue in the next line
total = tv + \
mobile + \
tablet

print(total)

65

# indentation
n = 9
r = 1

# while loop
while n > 0 :
    r = r * n
    n = n - 1

# print values after loop completed
print(r)

362880

str1 = 'hello'
str2 = "hello"
str3 = """hello
    world
"""
str4 = '''hello
world
'''

print(str1)
print(str2)
print(str3)
print(str4)

hello
hello
hello
    world

hello
world

age = 20; print(age); print("Age : " + str(age))

20
Age : 20

print("Hello \nWorld")

Hello 
World

print("Hello\tWorld")

Hello	World

print('Hello\tWorld')

Hello	World

name = input("Enter name")
print(name)

# get a number and convert to integer
number = int(input("Enter a new number"))
print(number)

total = number * 2
print(total)

# repeat the string value
print(name * 3)
print('-' * 20)

34
55
110
343434
--------------------

print(name + str(number))

3455

# define 3 variables at the same and all have same value
a = b = c = 99
print(a)
print(b)
print(c)

a = 88
print(a)
print(b)
print(c)

99
99
99
88
99
99

# define 3 variables at the same and all have different values
name, email, age = "John", "john@example.com", 30
print(name + " " + email + " " + str(age))

John john@example.com 30

print("pi = %s" % "3.14159")

pi = 3.14159

print("pi = %.5f" % 3.14159)

pi = 3.14159

print("pi is <%-6.2f>" % 3.14159)
print("pi is <%6.2f>" % 3.14159)

pi is <3.14  >
pi is <  3.14>

# using the % to do formatting sequences

(name, email, age) = ("John", "john@example.com", 30)

print("Name : %s, Email : %s, Age : %d" % (name, email, age))

print("%s\t%s\t%6.3f" % (name, email, age))

# assign new values to name, email and age
(name, email, age) = ("Bob", "bob@example.com", 35)
print("%s\t%s\t%6.3f" % (name, email, age))

Name : John, Email : john@example.com, Age : 30
John	john@example.com	30.000
Bob	bob@example.com	35.000

# use the format() with numerical index
print("Name : {0}, Email : {1}, Age: {2}".format(name, email, age))
print("Age: {0}, Name : {0}, Email : {1}".format(name, email, age))

Name : Bob, Email : bob@example.com, Age: 35
Age: Bob, Name : Bob, Email : bob@example.com

# use name instead
print("Name : {n}, Email : {e}, Age : {a}".format(n=name, e=email, a=age))
print("Age : {a}, Name : {n}, Email : {e}".format(n=name, e=email, a=age))

Name : Bob, Email : bob@example.com, Age : 35
Age : 35, Name : Bob, Email : bob@example.com

print("{0:10} is the food of gods".format("Ambrossia"))
print("{0:10} is the food of gods".format("Ambrossiaccc"))
print("{0:{1}} is the food of gods".format("Ambrossia", 10))
print("{food:{width}} is the food of gods".format(food="Ambrossia", width=10))
print("{0:>10} is the food of gods".format("Ambrossia"))    # right-align
print("{0:&>10} is the food of gods".format("Ambross"))   # right-align, replace whitespace with &

Ambrossia  is the food of gods
Ambrossiaccc is the food of gods
Ambrossia  is the food of gods
Ambrossia  is the food of gods
 Ambrossia is the food of gods
&&&Ambross is the food of gods

# named parameters and formatting sequences
num_dict = {'e' : 2.718, 'pi' : 3.14159}
print("%(pi).2f - %(pi).4f - %(e).2f" % num_dict)

3.14 - 3.1416 - 2.72

import time 
localtime = time.asctime(time.localtime(time.time()))
print("Formatted time : ", localtime)

Formatted time :  Fri Feb 26 12:03:12 2021

import calendar
calendar.prcal(2021)

                                  2021

      January                   February                   March
Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
             1  2  3       1  2  3  4  5  6  7       1  2  3  4  5  6  7
 4  5  6  7  8  9 10       8  9 10 11 12 13 14       8  9 10 11 12 13 14
11 12 13 14 15 16 17      15 16 17 18 19 20 21      15 16 17 18 19 20 21
18 19 20 21 22 23 24      22 23 24 25 26 27 28      22 23 24 25 26 27 28
25 26 27 28 29 30 31                                29 30 31

       April                      May                       June
Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
          1  2  3  4                      1  2          1  2  3  4  5  6
 5  6  7  8  9 10 11       3  4  5  6  7  8  9       7  8  9 10 11 12 13
12 13 14 15 16 17 18      10 11 12 13 14 15 16      14 15 16 17 18 19 20
19 20 21 22 23 24 25      17 18 19 20 21 22 23      21 22 23 24 25 26 27
26 27 28 29 30            24 25 26 27 28 29 30      28 29 30
                          31

        July                     August                  September
Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
          1  2  3  4                         1             1  2  3  4  5
 5  6  7  8  9 10 11       2  3  4  5  6  7  8       6  7  8  9 10 11 12
12 13 14 15 16 17 18       9 10 11 12 13 14 15      13 14 15 16 17 18 19
19 20 21 22 23 24 25      16 17 18 19 20 21 22      20 21 22 23 24 25 26
26 27 28 29 30 31         23 24 25 26 27 28 29      27 28 29 30
                          30 31

      October                   November                  December
Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su      Mo Tu We Th Fr Sa Su
             1  2  3       1  2  3  4  5  6  7             1  2  3  4  5
 4  5  6  7  8  9 10       8  9 10 11 12 13 14       6  7  8  9 10 11 12
11 12 13 14 15 16 17      15 16 17 18 19 20 21      13 14 15 16 17 18 19
18 19 20 21 22 23 24      22 23 24 25 26 27 28      20 21 22 23 24 25 26
25 26 27 28 29 30 31      29 30                     27 28 29 30 31

# conditional statements
x = 5

if x == 5 :
    print("equal 5")
elif x > 5 :
    print("greater than 5")
else :
    print("less than 5")

equal 5

# iterate 1 to 5 and display value
for v in range(1, 6) :
    print(v)

1
2
3
4
5

for v in range(5) :
    print(v)

0
1
2
3
4

for v in range(2, 30, 2) :
    print(v)

2
4
6
8
10
12
14
16
18
20
22
24
26
28

# list of fruit names
fruits = ["apple", "banana", "cherry"]
for f in fruits :
    print(f)

apple
banana
cherry

name = "John Smith"
for s in name :
    print(s)

J
o
h
n
 
S
m
i
t
h

# stop looping when f is banana - break : exit from the current block
for f in fruits :
    print(f)
    if f == "banana" :
        break

apple
banana

# continue : go to next iteration/item
for f in fruits :
    if f == "banana" :
        continue
    print(f)

apple
cherry

# while-loop 1 to 5
i = 1
while i <= 5 :
    print(i)
    i += 1

1
2
3
4
5

i = 1
while i <= 5 :
    if i == 3 :
        break
    print(i)
    i += 1

1
2

i = 1
while i <= 5 :
    i += 1
    if i == 3 :
        continue
    print(i)
    

2
4
5
6

# use while loop to iterate fruits
i = 0
while i < len(fruits) :
    print(fruits[i])
    i += 1

apple
banana
cherry

number = "abc"  # user input - string

try :
    total = int(number) + 2
except :
    print("cannot convert to int")

cannot convert to int

# example of string slicing
title = "Python Data Science"
print(title)

subtitle = title[0:5]
print(subtitle)

subtitle = title[5:]
print(subtitle)

subtitle = title[:5]
print(subtitle)

subtitle = title[5:10]
print(subtitle)

subtitle = title[-5:]
print(subtitle)

subtitle = title[:-5]
print(subtitle)

Python Data Science
Pytho
n Data Science
Pytho
n Dat
ience
Python Data Sc

subtext = "Python"
print(subtext in title)

subtext = "python"
print(subtext in title)

subtext = "python"
print(subtext not in title)

True
False
True

# use lambda to define anonymous function
sum = lambda val1, val2 : val1 + val2

# call sum function and display result
print("Total: ", sum(1, 2))

Total:  3

# use python syntax to define function
def add(val1, val2) :
    return val1 + val2

print("Total: ", add(1, 2))

Total:  3