String Methods
Python has a number of built-in methods that you can use on strings to do simple transformations.
You can see a comprehensive list via the link in the References.
1. What is a Method?
A method is something you can call on an object that does something with that object. This will make more sense when we get to object-orientation later in the course.
For now, if we have a string we can call a method using the . notation and we will get back a new string.
For example, type the following into the terminal,
"hello world".upper()
returns the new string:
"HELLO WORLD"
Here we called the upper() method on the str object "hello world" and it gave us back the str "HELLO WORLD".
1.1 Be Careful
String methods return new strings, consider the following code:
a = "hello world" # (assign "hello world" to variable a)
a.upper() # (call upper() on variable a)
print(a) # (print a)
will output
hello world
This is because it returns a new string, it does NOT change the original string. So a is left as "hello world".
We would either have to do the following to print out the upper case version,
a = "hello world" # (assign "hello world" to variable a)
print(a.upper()) # (print out the result of calling upper() on variable a)
or,
a = "hello world" # (assign "hello world" to variable a)
b = a.upper() # (call upper() on variable a and assign result to variable b)
print(b) # (print b)
1.2 Familiarise Yourself
Take a look at the following link - W3Schools - Python String Methods and try some of these out. You will need some of them for the TASK.
=== TASK ===
Copy the following into a new Python file.
sentence = input("Please enter a sentence:\n")
print(sentence)
Amend the code so that the inputted sentence is then printed out as
- upper case
- lower case
- first character of each word is upper case
For example,
Please enter a sentence:
The quick brown fox jumps over the lazy dog
THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG
the quick brown fox jumps over the lazy dog
The Quick Brown Fox Jumps Over The Lazy Dog