Expert Guidance for MSc, BIT, BSc, HND Projects: PHP, Python Automation, Freelancing and ICT Tuition: Python Data Types Built-in Data Types Numbers Casting String Booleans | Online ICT Technology Classes English Tamil Medium GCE OL AL

Python Data Types

1. Built-in Data Types

Data types are essential as they define the kind of operations variables can perform.
Categories of Python Data Types:
- Text Type: str
- Numeric Types: int, float, complex
- Sequence Types: list, tuple, range
- Mapping Type: dict
- Set Types: set, frozenset
- Boolean Type: bool
- Binary Types: bytes, bytearray, memoryview
- None Type: NoneType

2. Getting the Data Type

Use the type() function to determine the type of any object.
```
x = 5
print(type(x))  # Output: <class 'int'>
```

3. Setting the Data Type

Data type is assigned based on the value assigned to a variable.

Examples:
- x = "Hello World" → str
- x = 20 → int
- x = 20.5 → float
- x = 1j → complex
- x = ["apple", "banana", "cherry"] → list
- x = ("apple", "banana", "cherry") → tuple
- x = range(6) → range
- x = {"name": "John", "age": 36} → dict
- x = {"apple", "banana", "cherry"} → set
- x = frozenset({"apple", "banana", "cherry"}) → frozenset
- x = True → bool
- x = b"Hello" → bytes
- x = bytearray(5) → bytearray
- x = memoryview(bytes(5)) → memoryview
- x = None → NoneType

4. Setting Specific Data Types

Use constructor functions to specify the data type.

Examples:
- x = str("Hello World") → str
- x = int(20) → int
- x = float(20.5) → float
- x = complex(1j) → complex
- x = list(("apple", "banana", "cherry")) → list
- x = tuple(("apple", "banana", "cherry")) → tuple
- x = range(6) → range
- x = dict(name="John", age=36) → dict
- x = set(("apple", "banana", "cherry")) → set
- x = frozenset(("apple", "banana", "cherry")) → frozenset
- x = bool(5) → bool
- x = bytes(5) → bytes
- x = bytearray(5) → bytearray
- x = memoryview(bytes(5)) → memoryview

5. Quiz/Exercise

Question: If x = 5, what is the correct syntax for printing the data type of x?
- Correct Answer: print(type(x))

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Python Numbers

Three Numeric Types in Python:
- int: Integer (whole numbers, positive or negative, without decimals, unlimited length).
- float: Floating-point number (numbers with decimals or in scientific notation).
- complex: Complex number (with a real and imaginary part, written as a + bj).

Creating Numeric Variables:

x = 1    # int
y = 2.8  # float
z = 1j   # complex

Verifying the Type of an Object: Use the type() function.
```
print(type(x))
print(type(y))
print(type(z))
```

Details of Numeric Types

1. Int (Integer):

Whole numbers without decimals.
Positive, negative, or zero.
Unlimited length.

x = 1
y = 35656222554887711
z = -3255522

print(type(x))
print(type(y))
print(type(z))

2. Float (Floating-Point Numbers):

Numbers containing one or more decimals.
Can also represent scientific numbers using e for powers of 10.

x = 1.10
y = 1.0
z = -35.59

x = 35e3
y = 12E4
z = -87.7e100

print(type(x))
print(type(y))
print(type(z))

3. Complex Numbers:

Written with a "j" to represent the imaginary part.

x = 3+5j
y = 5j
z = -5j

print(type(x))
print(type(y))
print(type(z))

Type Conversion

Convert between numeric types using int(), float(), and complex().

x = 1    # int
y = 2.8  # float
z = 1j   # complex

a = float(x)  # Convert int to float
b = int(y)    # Convert float to int
c = complex(x)  # Convert int to complex

print(a)
print(b)
print(c)

print(type(a))
print(type(b))
print(type(c))

Note: Complex numbers cannot be converted to other numeric types.

Random Numbers

Python does not have a built-in random() function but includes a random module.
Use the random.randrange(start, stop) function to generate a random number.
```
import random

print(random.randrange(1, 10))
```

Quiz/Exercise:

Question: Which is NOT a legal numeric data type in Python?

int
long (Correct Answer: long is not valid; it was part of Python 2.)
float

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Here are the key points extracted from the content:

Python Casting

1. Purpose of Casting

Casting is used to specify the data type of a variable explicitly.
Python, being an object-oriented language, uses classes to define data types.

2. Constructor Functions for Casting

int()
Constructs an integer:
- From an integer literal.
- From a float literal (removing decimals).
- From a string literal (if the string represents a whole number).
- Examples:
```
x = int(1)      # x will be 1
y = int(2.8)    # y will be 2 (decimals are removed)
z = int("3")    # z will be 3
```
float()
Constructs a floating-point number:
- From an integer literal.
- From a float literal.
- From a string literal (if the string represents a number).
- Examples:
```
x = float(1)       # x will be 1.0
y = float(2.8)     # y will be 2.8
z = float("3")     # z will be 3.0
w = float("4.2")   # w will be 4.2
```

str()
Constructs a string:

From strings.
From integers.
From floats.

Examples:

x = str("s1")  # x will be 's1'
y = str(2)     # y will be '2'
z = str(3.0)   # z will be '3.0'

3. Quiz/Exercise

Question: What will be the result of the following code?
```
print(int(35.88))
```
- Correct Answer: 35
  (The decimals are truncated when casting a float to an integer.)

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Here are all the key points from the content about Python Booleans:

Python Booleans

1. Boolean Representation

Booleans represent one of two values: True or False.

2. Boolean Values

Any expression in Python can be evaluated to True or False.

Comparison Examples:

print(10 > 9)   # True
print(10 == 9)  # False
print(10 < 9)   # False

3. Booleans in Conditional Statements

When used in an if statement, Python evaluates the condition and returns True or False.

Example:

a = 200
b = 33

if b > a:
  print("b is greater than a")
else:
  print("b is not greater than a")

4. The `bool()` Function

Purpose: Evaluates any value and returns True or False.

Examples:

print(bool("Hello"))  # True
print(bool(15))       # True

x = "Hello"
y = 15
print(bool(x))        # True
print(bool(y))        # True

5. Most Values are `True`

Non-empty strings, numbers (non-zero), and collections (non-empty lists, tuples, sets, dictionaries) evaluate to True.

Examples:

print(bool("abc"))                      # True
print(bool(123))                        # True
print(bool(["apple", "cherry", "banana"]))  # True

6. Some Values are `False`

Values that evaluate to False include:

Empty values: (), [], {}, "".
The number 0.
None.
The value False.

Examples:

print(bool(False))  # False
print(bool(None))   # False
print(bool(0))      # False
print(bool(""))     # False
print(bool(()))     # False
print(bool([]))     # False
print(bool({}))     # False

7. Special Case: Custom Objects

Objects with a __len__ method that returns 0 or False evaluate to False.

Example:

class myclass():
  def __len__(self):
    return 0

myobj = myclass()
print(bool(myobj))  # False

8. Functions Returning a Boolean

Functions can return Boolean values and can be used in conditions.

Example:

def myFunction():
  return True

print(myFunction())  # True

if myFunction():
  print("YES!")
else:
  print("NO!")

9. Built-in Boolean Functions

Python includes functions like isinstance() to check data types, which return True or False.
- Example:
```
x = 200
print(isinstance(x, int))  # True
```

10. Quiz/Exercise

Question: What will be the result of the following syntax?
```
print(5 > 3)
```
- Correct Answer: True

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Monday, December 23, 2024

Python Data Types Built-in Data Types Numbers Casting String Booleans | Online ICT Technology Classes English Tamil Medium GCE OL AL

Python Data Types

1. Built-in Data Types

2. Getting the Data Type

3. Setting the Data Type

4. Setting Specific Data Types

5. Quiz/Exercise

Python Numbers

Details of Numeric Types

1. Int (Integer):

2. Float (Floating-Point Numbers):

3. Complex Numbers:

Type Conversion

Random Numbers

Quiz/Exercise:

Python Casting

1. Purpose of Casting

2. Constructor Functions for Casting

3. Quiz/Exercise

Python Booleans

1. Boolean Representation

2. Boolean Values

3. Booleans in Conditional Statements

4. The `bool()` Function

5. Most Values are `True`

6. Some Values are `False`

7. Special Case: Custom Objects

8. Functions Returning a Boolean

9. Built-in Boolean Functions

10. Quiz/Exercise

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Main Menu

Monday, December 23, 2024

Python Data Types Built-in Data Types Numbers Casting String Booleans | Online ICT Technology Classes English Tamil Medium GCE OL AL

Python Data Types

1. Built-in Data Types

2. Getting the Data Type

3. Setting the Data Type

4. Setting Specific Data Types

5. Quiz/Exercise

Python Numbers

Details of Numeric Types

1. Int (Integer):

2. Float (Floating-Point Numbers):

3. Complex Numbers:

Type Conversion

Random Numbers

Quiz/Exercise:

Python Casting

1. Purpose of Casting

2. Constructor Functions for Casting

3. Quiz/Exercise

Python Booleans

1. Boolean Representation

2. Boolean Values

3. Booleans in Conditional Statements

4. The bool() Function

5. Most Values are True

6. Some Values are False

7. Special Case: Custom Objects

8. Functions Returning a Boolean

9. Built-in Boolean Functions

10. Quiz/Exercise

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Post a Comment

4. The `bool()` Function

5. Most Values are `True`

6. Some Values are `False`