Python Casting
In Python, casting refers to the process of changing the data type of a variable or value from one type to another.
This can be useful when you need to perform operations on different types of data or when you need to ensure that the data you are working with is in the correct format.
Python provides several built-in functions for casting:
- int() – converts a value to an integer
- float() – converts a value to a floating-point number
- str() – converts a value to a string
- bool() – converts a value to a boolean
You can also use casting to convert between different types of collections, such as lists, tuples, and dictionaries.
When casting, it’s important to be aware of potential issues that may arise, such as the loss of precision when converting from a floating-point number to an integer.
It’s also important to be mindful of the type of data you are working with and ensure that the casting operation is appropriate for your specific use case.
Here are some examples of Python casting:
Contents
Converting a string to an integer
How to convert string into integer in python?
string_num = "10" int_num = int(string_num) print(int_num) # Output: 10
Converting a floating-point number to an integer in python
How to convert floating into integer in python?
float_num = 3.14 int_num = int(float_num) print(int_num) # Output: 3
Converting an integer to a string in python
How to convert integer into string in python?
int_num = 10 string_num = str(int_num) print(string_num) # Output: "10"
Converting a string to a boolean in python
How to convert string into boolean ?
string_bool = "True" bool_val = bool(string_bool) print(bool_val) # Output: True
Converting a list to a tuple in python
How to convert list into tuple in python?
my_list = [1, 2, 3] my_tuple = tuple(my_list) print(my_tuple) # Output: (1, 2, 3)
Converting a dictionary to a list in python
How to convert dictionary into a list in python?
my_dict = {"name": "John", "age": 30}
my_list = list(my_dict.items())
print(my_list) # Output: [("name", "John"), ("age", 30)]
Converting a string to a floating-point number in python
How to convert string into a list in python?
string_num = "3.14" float_num = float(string_num) print(float_num) # Output: 3.14
Converting a boolean to an integer in python
How to covert boolean into a integer in python?
bool_val = True int_num = int(bool_val) print(int_num) # Output: 1
Converting a tuple to a list
How to convert tuple into a list in python?
my_tuple = (1, 2, 3) my_list = list(my_tuple) print(my_list) # Output: [1, 2, 3]
Converting a list of strings to a list of integers
How to convert list into a strings in python?
my_list = ["1", "2", "3"] int_list = [int(num) for num in my_list] print(int_list) # Output: [1, 2, 3]
Converting a list of integers to a string
How to convert list into integers in python?
my_list = [1, 2, 3] string_list = [str(num) for num in my_list] string_nums = ", ".join(string_list) print(string_nums) # Output: "1, 2, 3"
Converting a dictionary to a set
How to convert dictionary into set in python?
my_dict = {"apple": 1, "banana": 2, "orange": 3}
my_set = set(my_dict.values())
print(my_set) # Output: {1, 2, 3}
Converting a set to a list
How to convert set into list in python?
my_set = {1, 2, 3}
my_list = list(my_set)
print(my_list) # Output: [1, 2, 3]
Converting a string to a list
How to convert string into list in python?
my_string = "Hello, World!" my_list = list(my_string) print(my_list) # Output: ['H', 'e', 'l', 'l', 'o', ',', ' ', 'W', 'o', 'r', 'l', 'd', '!']
Converting a list of integers to a set
How to convert a list into set in python?
my_list = [1, 2, 3, 1, 2, 3]
my_set = set(my_list)
print(my_set) # Output: {1, 2, 3}
Converting a tuple of strings to a dictionary
How to convert a tuple into a dictionary in python?
my_tuple = ("name", "John", "age", "30")
my_dict = dict(zip(my_tuple[::2], my_tuple[1::2]))
print(my_dict) # Output: {"name": "John", "age": "30"}
Converting a string to a boolean
How to convert a string into a boolean in python?
my_string = "True" my_bool = my_string.lower() == "true" print(my_bool) # Output: True
Converting a list of tuples to a dictionary
How to convert a list of tuples into a dictionary in python?
my_list = [("name", "John"), ("age", 30)]
my_dict = dict(my_list)
print(my_dict) # Output: {"name": "John", "age": 30}
Quiz: Python Casting
1-What is casting in Python?
a. Creating new variables
b. Changing the data type of a variable or value from one type to another
c. Performing mathematical operations
d. Printing values to the console
2-Which of the following functions is used to convert a value to an integer in Python?
a. toint()
b. int()
c. convert_int()
d. integer()
3-What can casting be useful for in Python?
a. Creating new variables
b. Changing the format of a string
c. Performing operations on different types of data
d. Both b and c
4-Which function is used to convert a value to a floating-point number in Python?
a. tofloat()
b. float()
c. convert_float()
d. floating()
5-When converting a floating-point number to an integer in Python, what potential issue should you be aware of?
a. Loss of precision
b. Increased precision
c. No issues
d. Loss of decimal points
6-How can you convert a string to a boolean in Python?
a. bool(str_value)
b. tobool(str_value)
c. boolean(str_value)
d. bool()
7-Which function converts a list to a tuple in Python?
a. list_to_tuple()
b. tuple()
c. convert_to_tuple()
d. to_tuple()
8-How can you convert a boolean to an integer in Python?
a. int(bool_value)
b. toint(bool_value)
c. integer(bool_value)
d. int()
9-What is an important consideration when casting from a floating-point number to an integer in Python?
a. Loss of precision
b. No considerations needed
c. Increase in precision
d. Automatic rounding
10-How can you convert a list of strings to a list of integers in Python?
a. convert_list_to_int()
b. int_list()
c. [int(num) for num in my_list]
d. toint(my_list)
Answers:
1-b
2-b
3-d
4-b
5-a
6-d
7-b
8-a
9-a
10-c
Quiz 2
1-How can you convert a dictionary to a list in Python?
a. list_dict()
b. convert_dict_to_list()
c. list(my_dict.items())
d. dict_to_list()
2-What function is used to convert a string to a floating-point number in Python?
a. float()
b. tofloat()
c. convert_float()
d. string_to_float()
3-How do you convert a list of integers to a string in Python?
a. str_list()
b. [str(num) for num in my_list]
c. convert_list_to_str()
d. str()
4-What is the output of the following code?
my_set = set([1, 2, 3, 1, 2, 3])
print(my_set)
a. [1, 2, 3]
b. (1, 2, 3)
c. {1, 2, 3}
d. [1, 2, 3, 1, 2, 3]
5-How can you convert a set to a list in Python?
a. list_set()
b. set_to_list()
c. list(my_set)
d. convert_set_to_list()
6-In the context of Python casting, what does the join function do?
a. Joins two strings together
b. Combines elements of a list into a string
c. Concatenates two dictionaries
d. Converts a string to a boolean
7-How do you convert a tuple to a dictionary in Python?
a. dict(my_tuple)
b. tuple_to_dict()
c. convert_tuple_to_dict()
d. {key: value for key, value in my_tuple}
8-What is the output of the following code?
my_string = “Hello, World!”
my_list = list(my_string)
print(my_list)
a. Hello, World!
b. [‘H’, ‘e’, ‘l’, ‘l’, ‘o’, ‘,’, ‘ ‘, ‘W’, ‘o’, ‘r’, ‘l’, ‘d’, ‘!’]
c. [‘Hello’, ‘World’]
d. H e l l o , W o r l d !
9-How can you convert a list of tuples to a dictionary in Python?
a. dict_from_tuples()
b. convert_to_dict()
c. dict(my_list)
d. {key: value for key, value in my_list}
10-What is the purpose of the zip function in the context of Python casting?
a. Converts a list to a tuple
b. Combines multiple iterables into tuples
c. Converts a dictionary to a set
d. Checks if two variables have the same type
Quiz 3
1-How can you convert a boolean to a string in Python?
a. str(bool_val)
b. tostr(bool_val)
c. string(bool_val)
d. str()
2-What is the output of the following code?
my_tuple = (“name”, “John”, “age”, “30”)
my_dict = dict(zip(my_tuple[::2], my_tuple[1::2]))
print(my_dict)
a. {“name”: “John”, “age”: “30”}
b. {“name”: “John”, “age”: 30}
c. {(“name”, “John”), (“age”, “30”)}
d. [(“name”, “John”), (“age”, “30”)]
3-In Python, what potential issue should you be aware of when converting a string to a boolean?
a. No potential issues
b. Loss of precision
c. Case sensitivity
d. Unexpected values may result in errors
4-How can you convert a list of integers to a set in Python?
a. set_list()
b. convert_list_to_set()
c. set(my_list)
d. toset(my_list)
5-What function is used to convert a set to a list in Python?
a. list_set()
b. set_to_list()
c. list(my_set)
d. convert_set_to_list()
6-What is the output of the following code?
my_dict = {“apple”: 1, “banana”: 2, “orange”: 3}
my_set = set(my_dict.values())
print(my_set)
a. {“apple”: 1, “banana”: 2, “orange”: 3}
b. {1, 2, 3}
c. [1, 2, 3]
d. (“apple”, “banana”, “orange”)
7-How can you convert a list of strings to a list of integers in Python?
a. convert_list_to_int()
b. int_list()
c. [int(num) for num in my_list]
d. toint(my_list)
8-What is the output of the following code?
python
Copy code
my_list = [“1”, “2”, “3”]
int_list = [int(num) for num in my_list]
print(int_list)
a. [“1”, “2”, “3”]
b. [1, 2, 3]
c. (“1”, “2”, “3”)
d. (“1”, 2, “3”)
9-How can you convert a list of integers to a string in Python?
a. str_list()
b. [str(num) for num in my_list]
c. convert_list_to_str()
d. str()
10-What function is used to convert a tuple to a list in Python?
a. list_to_tuple()
b. tuple()
c. convert_to_tuple()
d. to_tuple()