If you are learning to program, then mastering the Python map function is your chance to upgrade.
Picture this: you want to be a more efficient programmer, you want code to compile faster, and you want to impress your peers with your strong programming knowledge. If any of these points resonate with you, then you've come to the right place.
Before we continue, you need to understand what functions and iterable objects are:
A function is code that performs a specific task.
Example:len(), print(), str()
An iterable object is an object that contains one or more items.
Example:listings、dictionaries、tuple
The Python map function is a function that allows you to convert an entire iterable object using another function. The key concept here is transformation, which can include but is not limited to:
- Converting strings to numbers
- rounded figure
- Get the length of each iterable
You may be wondering, "Why can't I do the above with a for loop?"
The answer is: you can. But using the Python map function saves memory (which means your code runs faster) and requires less code. Let's walk through an example to show what I mean.
Let's start with the for loop
Suppose you have a list of strings consisting of numbers and you need to convert the list of strings to integers:
list_of_strings = ["5","6","7","8","9", "10"]
You can do this with an empty list and a for loop:
list_of_strings = ["5","6","7","8","9", "10"]
result = []
for string in list_of_strings:
(int(string))
print(result)
The result of this example run is:
Output: [5, 6, 7, 8, 9, 10]
What's going on behind the for loop?
You may be happy with the results, but think about what your code just did.
You tell the computer to iterate over each item ("5", "6", "7", etc.), convert the item, and then store that item in a new list. While using a for loop to convert the list is efficient, it is not optimal.
Python map function (with sample code)
Instead, let's use the Python map function to generate the best results. We'll start with a list of strings that need to be converted:
list_of_strings = ["5","6","7","8","9", "10"]
We'll then use the Python map function to convert the list of strings to a list of integers:
result = map(int,list_of_strings) print(list(result))
If you run the example above, you'll get the same result:
Output: [5, 6, 7, 8, 9, 10]
Before we get into why the Python map function is better than using a for loop, let's break down what we just did:
list_of_strings = ["5","6","7","8","9", "10"]
All we're doing here is creating a variable to store the list of strings we want to convert to numbers.
result = map(int,list_of_strings)
Let's break down the above code from the inside out. the syntax of the Python map function is as follows:
map(insert function here, insert iterable here)
map() It's just the name of the Python map function, nothing special.
insert function here is the space you will write to in the function. In the code example above, we used the int function. We could have used another built-in function, such as len(), or we could have built our own function and used it here as well.
insert iterable here is the space you will write to in the iterable project of your choice. In this example, we are inserting lists (list_of_strings).
result is the variable where we store the newly converted items.
Let's move to the last line of code. Again, it will be executed from the inside out:
print(list(result))
list() Receive our newly converted iterable items and tell our computer that they are part of a list.
print() Print out our new list!
What's going on behind the scenes in Python's map function
Instead of iterating through each item of a list of strings, the Python map function converts the entire list of strings into a list of numbers. You save memory and the code runs faster.
If you want to transform items, it's better to use the Python map function than a for loop.
Finally.Python map Functions are more elegant than for loops and will help you compile your code faster.
Using the Python map function will help take your programming skills to the next level, making you a better programmer. In the process, you can even impress your peers with this new skill.
summarize
The Python map function is just the beginning. There are many more Python tricks to help you write more elegant code and improve your programming skills. Have fun learning!
That's all for this post, I hope it was helpful and I hope you'll check back for more from me!