Type Conversion Functions

Type Conversion Functions in Python 🔄

Type conversion (or type casting) transforms data from one type to another. Python provides built-in functions for these conversions. Here’s a comprehensive guide with examples:

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1. int(x) 🔢

Converts x to an integer.

Python

print(int(3.14))        # 3 (float → int)
print(int("42"))        # 42 (str → int)
print(int(True))        # 1 (bool → int)
print(int("1010", 2))   # 10 (binary str → int)
# print(int("Hello"))   # ❌ ValueError (non-numeric string)

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2. float(x) afloat

Converts x to a floating-point number.

Python

print(float(42))        # 42.0 (int → float)
print(float("3.14"))    # 3.14 (str → float)
print(float(False))     # 0.0 (bool → float)
# print(float("1a.5"))  # ❌ ValueError (invalid string)

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3. str(x) 💬

Converts x to a string. Works with any data type.

Python

print(str(100))         # '100' (int → str)
print(str(7.8e-2))      # '0.078' (float → str)
print(str([1, 2, 3]))   # '[1, 2, 3]' (list → str)
print(str(True))        # 'True' (bool → str)

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4. bool(x) ✅❌

Converts x to a Boolean (True or False).

Falsy values: 0, 0.0, “”, [], (), {}, None

Truthy values: Everything else.

Python

print(bool(0))          # False (int)
print(bool("Hello"))    # True (non-empty str)
print(bool([]))         # False (empty list)
print(bool(3.14))       # True (non-zero float)

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5. list(x) 📋

Converts iterable x to a list.

Python

print(list("abc"))      # ['a', 'b', 'c'] (str → list)
print(list((1, 2, 3)))  # [1, 2, 3] (tuple → list)
print(list({4, 5, 6}))  # [4, 5, 6] (set → list; order not guaranteed)
print(list({'a': 1}))   # ['a'] (dict → list of keys)

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6. tuple(x) 📦

Converts iterable x to a tuple.

Python

print(tuple([1, 2, 3])) # (1, 2, 3) (list → tuple)
print(tuple("hi"))      # ('h', 'i') (str → tuple)

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7. set(x) 📚

Converts iterable x to a set (removes duplicates).

Python

print(set([1, 2, 2, 3])) # {1, 2, 3} (list → set)
print(set("apple"))      # {'a', 'p', 'l', 'e'} (str → set)

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8. dict(x) 🗺️

Converts iterable of key-value pairs to a dictionary.

Python

print(dict([('a', 1), ('b', 2)]))  # {'a': 1, 'b': 2} (list of tuples → dict)
print(dict(a=1, b=2))              # {'a': 1, 'b': 2} (keyword args → dict)

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9. chr(x) & ord(x) 🅰️➡️🔢

• chr(i): Converts Unicode code point i to a character.
• ord(c): Converts character c to its Unicode code point.

Python

print(chr(65))          # 'A' (int → char)
print(ord('A'))         # 65 (char → int)
print(chr(128512))      # '😀' (emoji)

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10. bin(x), oct(x), hex(x) 🔢➡️🔡

Convert integers to string representations in different bases.

Python

print(bin(42))          # '0b101010' (int → binary str)
print(oct(42))          # '0o52' (int → octal str)
print(hex(42))          # '0x2a' (int → hexadecimal str)

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Implicit vs. Explicit Conversion ➡️

→ Implicit (Automatic) 🤖

Python automatically converts types during operations:

Python

result = 3 + 4.5    # int(3) → float, result=7.5 (float)

→ Explicit (Manual) ✍️

Programmer specifies the conversion:

Python

age = "25"
years_to_100 = 100 - int(age)  # Explicit str → int

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Key Rules & Errors 🚨

1. Compatibility:Python# int("12.3") # ❌ ValueError (float string → int) print(float("12.3")) # ✅ 12.3
2. Collections:Python# list(123) # ❌ TypeError (int not iterable)
3. Dictionary Conversion:Requires iterable of key-value pairs:Pythonprint(dict([('a', 1), ('b', 2)])) # ✅ Valid # dict([1, 2, 3]) # ❌ TypeError (not key-value pairs)

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Practical Example 💡

Python

# Calculate average from user input (str → float)
scores = ["85.5", "90", "78.5"]
numeric_scores = [float(score) for score in scores]  # Convert list of str to float
average = sum(numeric_scores) / len(numeric_scores)
print(f"Average: {average:.2f}")  # Output: Average: 84.67

Mastering type conversions is essential for data processing and user input handling! 🚀