Booleans and Number in Python

Booleans in Python¶

• Boolean values in Python represent one of two values : True and False. - -
• Booleans are often used for conditional statements, comparisons, and controlling the flow of a program.

Boolean Values:¶

• In Python, True and False are reserved keywords representing the boolean values.

In [ ]:

x = True
y = False

Boolean Operators:¶

• Python provides several operators for working with boolean values.

  • and: Returns True if both operands are True.
  • or: Returns True if at least one operand is True.
  • not: Returns the opposite of the boolean operand.

In [ ]:

a = True
b = False

result1 = a and b  # False
result2 = a or b   # True
result3 = not a    # False

print(result1)
print(result2)
print(result3)

False
True
False

Comparison Operators:¶

• You can compare values using comparison operators, which return boolean results.

  ==: Equal to
  !=: Not equal to
  <: Less than
  <=: Less than or equal to
  >: Greater than
  >=: Greater than or equal to

In [ ]:

num1 = 5
num2 = 10

result1 = num1 == num2   # False
result2 = num1 < num2    # True
result3 = num1 != num2   # True

print(result1)
print(result2)
print(result3)

False
True
True

Conditional Statements:¶

• Booleans are commonly used in conditional statements like if, elif, and else to control program flow.

In [ ]:

age = 20

if age >= 18:
    print("You are an adult.")
else:
    print("You are a minor.")

You are an adult.

Boolean Conversion:¶

• You can convert other data types to boolean using the bool() constructor.
• In general, empty sequences (e.g., empty lists or strings) and numeric zeros are considered False, while non-empty sequences and non-zero numbers are considered True.

In [ ]:

bool_var = bool(0)      # False
bool_str = bool("Hello")  # True
bool_var1  = bool(15)

print(bool_var)
print(bool_str)
print(bool_var1)

False
True
True

Boolean Functions:¶

• You can create functions that return boolean values based on certain conditions.

In [ ]:

def is_even(number):
    return number % 2 == 0

print(is_even(4))   # True
print(is_even(7))   # False

True
False

• Python also has many built-in functions that return a boolean value, like the isinstance() function, which can be used to determine if an object is of a certain data type

In [ ]:

x = 200
print(isinstance(x, int))

True

Truthy Values:¶

• Values that are considered True in a boolean context:
  • Any non-empty string: "hello", "0", "False", etc.
  • Any non-zero number: 1, -1, 3.14, etc.
  • Any non-empty list, tuple, set, or dictionary: [1, 2, 3], ("apple", "banana"), {1, 2, 3}, {"key": "value"}.

In [ ]:

# Truthy values
if "hello":
    print("This is a truthy string.")

if 42:
    print("This is a truthy number.")

if [1, 2, 3]:
    print("This is a truthy list.")

This is a truthy string.
This is a truthy number.
This is a truthy list.

Falsy Values:¶

• Values that are considered False in a boolean context:
  • Empty strings: "" (an empty string is falsy).
  • The number 0 (zero is falsy).
  • Empty collections: [] (empty list), () (empty tuple), set() (empty set), {} (empty dictionary).

In [ ]:

# Falsy values
if "":
    print("This is an empty string (falsy).")

if 0:
    print("This is the number 0 (falsy).")

if []:
    print("This is an empty list (falsy).")

In [ ]:

# None also return false
bool(None)

Out[ ]:

False

Number in Python¶

• Numbers in Python come in different types, including integers, floating-point numbers, and complex numbers.
• Python supports four different numerical types :
  • int (signed integers)
  • long (long integers, they can also be represented in octal and hexadecimal)
  • float (floating point real values)
  • complex (complex numbers)

int	long	float	complex
5	51924361L	0.0	3.14j
5	-0x19323L	15.20	45.j
-9	0122L	-21.9	9.322e-36j
090	0xDEFABCECBDAECBFBAEl	32.3+e18	.876j
-0290	535633629843L	-90.	-.6545+0J
-0x160	-052318172735L	-32.54e100	3e+26J
0x64	-4721885298529L	70.2-E12	4.53e-7j

• Python allows you to use a lowercase l with long, but it is recommended that you use only an uppercase L to avoid confusion with the number. Python displays long integers with an uppercase L.

• A complex number consists of an ordered pair of real floating-point numbers denoted by x + yj, where x and y are the real numbers and j is the imaginary unit.

In [ ]:

# int
a = 1

#Float
b = 1.65

# Float can also be scientific numbers with an "e" to indicate the power of 10.
c = 40e1

#Complex
d = 1+2j

Functions for Data-Type Conversion¶

• Python provides several built-in functions for converting data from one data type to another. These functions return a new object representing the converted value, leaving the original object unchanged. Here are some commonly used data type conversion functions:

Function	Description
int(x [,base])	Converts x to an integer. base specifies the base if x is a string.
long(x [,base] )	Converts x to a long integer. base specifies the base if x is a string.
float(x)	Converts x to a floating-point number.
complex(real [,imag])	Creates a complex number.
str(x)	Converts object x to a string representation.
repr(x)	Converts object x to an expression string.
eval(str)	Evaluates a string and returns an object.
tuple(s)	Converts s to a tuple.
list(s)	Converts s to a list.
set(s)	Converts s to a set.
dict(d)	Creates a dictionary. d must be a sequence of (key,value) tuples.
frozenset(s)	Converts s to a frozen set.
chr(x)	Converts an integer to a character.
unichr(x)	Converts an integer to a Unicode character.
ord(x)	Converts a single character to its integer value.
hex(x)	Converts an integer to a hexadecimal string.
oct(x)	Converts an integer to an octal string.