TypeCasting in Python CheatSheet

Typecasting is converting a value from one data type to another in Python. This is useful when you need to perform operations on different data types.

Why Typecasting is Needed :

1. To perform calculations on strings that contain numbers

2. To convert data received from user input

3. To ensure compatibility between different data types

4. input() will always return data of string datatype

String To Integer

num_str = "10"
print(type(num_str))   # <class 'str'>
num_int = int(num_str) # "10" -> 10
print(type(num_int))   # <class 'int'>

<class 'str'>
<class 'int'>

String To Float

float_str = "3.14"
print(type(float_str))       # <class 'str'>
num_float = float(float_str) # "3.14" -> 3,.14
print(type(num_float))       # <class 'float'>

<class 'str'>
<class 'float'>

Converting a string containing a float value into an integer: Not Possible

num_str="3.14"
int_num = int(num_str)
print(int_num)   # Error -> converting a string containing float value into integer is not possible

Converting a String containing an integer into a float

num_str="3"
int_num = float(num_str)
print(int_num) # Output : 3.0

Converting a string value into an integer

string_var = "ConsoleFlare"
int_var = int(string_var)
print(int_var) # Error

Converting a string containing alphabets and numbers into Integers --> Not Possible

string_var="abcd12345"
int_var= int(string_var)
print(int_var)  # Error : Not Possible

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
Cell In[1], line 3
      1 # Converting a String containing alphabets and numbers into Integer -> Not Possible
      2 string_var="abcd12345"
----> 3 int_var= int(string_var)
      4 print(int_var)  # Error : Not Possible

ValueError: invalid literal for int() with base 10: 'abcd12345'

Integer to Float

num = 7
num_float = float(num) # 7 -> 7.0
print(num_float)  # Output: 7.0

Integer to String

num = 100
num_str = str(num) # 100 -> "100"
print("Number is " + num_str)  # Output: Number is 100

Float to Integer

num = 3.99
num_int = int(num)  # 3.99 -> 3
print(num_int)  # Output: 3

# Note: Float to integer is not like rounding off... In integer typecasting the point values get simply ignored

Float to String

float_num = 3.14
float_str=str(float_num)
print(float_str,type(float_str))  # Output : 3.14 <class 'str'>

3.14 <class 'str'>

Integer to Boolean

print(bool(0))   # Output: False
print(bool(5))   # Output: True

Float to Boolean

print(bool(0.0))   # Output: False
print(bool(5.5))   # Output: True

String to Boolean

print(bool(""))      # Output: False
print(bool("Hello")) # Output: True
print(bool("S"))     # Output: True
print(bool(" "))     # Output : True

False
True
True
True

Boolean to Integer

print(int(True))  # Output : 1
print(int(False)) # Output : 0

1
0

Boolean to Float

print(float(True))  # Output : 1.0
print(float(False))  # Output : 0.0

1.0
0.0

Boolean to String

print(str(True))  # Output : True (string datatype)
print(str(False))  # Output : False (string datatype)

True
False

User Input

age = int(input("Enter your age: "))
height = float(input("Enter your height in meters: "))
print("Next year you will be", age + 1)
print("If you grow, your height will be", height + 0.1)