Flash cards
Review the key moves
What is the main idea behind How to Reverse a String in Python?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
___ = "Hello World"[::-1]Put the learning moves in the order that makes the concept easiest to apply.
Learn how to reverse a String in Python.
There is no built-in function to reverse a String in Python.
The fastest (and easiest?) way is to use a slice that steps backwards, -1 .
Example
txt = "Hello World"[::-1]
print(txt)Example Explained
We have a string, "Hello World", which we want to reverse:
The String to Reverse
txt =
"Hello World"
[::-1]
print(txt)Create a slice that starts at the end of the string, and moves backwards.
In this particular example, the slice statement [::-1] means start at the end of the string and end at position 0, move with the step -1 , negative one, which means one step backwards.
Slice the String
txt = "Hello World"
[::-1]
print(txt)Now we have a string txt that reads "Hello World" backwards.
Print the String to demonstrate the result
Print the List
txt = "Hello World"[::-1]
print(txt)Create a Function
If you like to have a function where you can send your strings, and return them backwards, you can create a function and insert the code from the example above.
Example
def my_function(x):
return x[::-1]
mytxt =
my_function("I wonder how this text looks like backwards")
print(mytxt)Example Explained
Create a function that takes a String as an argument.
Create a Function
def my_function(x):
return x[::-1]
mytxt =
my_function("I wonder how this text looks like backwards")
print(mytxt)Slice the string starting at the end of the string and move backwards.
Slice the String
def my_function(x):
return x
[::-1]
mytxt =
my_function("I wonder how this text looks like backwards")
print(mytxt)Return the backward String
Return the String
def my_function(x):
return
x[::-1]
mytxt =
my_function("I wonder how this text looks like backwards")
print(mytxt )Call the function, with a string as a parameter:
Call the Function
def my_function(x):
return
x[::-1]
mytxt = my_function("I
wonder how this text looks like backwards")
print(mytxt)Print the Result
def my_function(x):
return
x[::-1]
mytxt = my_function("I wonder how this text looks like backwards")
print(mytxt)