Python Strings

String Literals

String literals in python are surrounded by either single quotation marks, or double quotation marks.

'hello' is the same as "hello".

Strings can be output to screen using the print function. For example: print("hello").

Like many other popular programming languages, strings in Python are arrays of bytes representing unicode characters. However, Python does not have a character data type, a single character is simply a string with a length of 1. Square brackets can be used to access elements of the string.

Example

Get the character at position 1 (remember that the first character has the position 0):

a = "Hello, World!"
print(a[1])

Show Python »
C:\Users\My Name>python demo_string1.py
e                                      
                                       
                                       

Example

Substring. Get the characters from position 2 to position 5 (not included):

b = "Hello, World!"
print(b[2:5])

Show Python »
C:\Users\My Name>python demo_string2.py
llo                                    
                                       
                                       

Example

The strip() method removes any whitespace from the beginning or the end:

a = " Hello, World! "
print(a.strip()) # returns "Hello, World!"

Show Python »
C:\Users\My Name>python demo_string_strip.py
Hello, World!                               
                                            
                                            

Example

The len() method returns the length of a string:

a = "Hello, World!"
print(len(a))

Show Python »
C:\Users\My Name>python demo_string_len.py
13                                        
                                          
                                          

Example

The lower() method returns the string in lower case:

a = "Hello, World!"
print(a.lower())

Show Python »
C:\Users\My Name>python demo_string_lower.py
hello, world!                               
                                            
                                            

Example

The upper() method returns the string in upper case:

a = "Hello, World!"
print(a.upper())

Show Python »
C:\Users\My Name>python demo_string_upper.py
HELLO, WORLD!                               
                                            
                                            

Example

The replace() method replaces a string with another string:

a = "Hello, World!"
print(a.replace("H", "J"))

Show Python »
C:\Users\My Name>python demo_string_replace.py
Jello, World!                                 
                                              
                                              

Example

The split() method splits the string into substrings if it finds instances of the separator:

a = "Hello, World!"
print(a.split(",")) # returns ['Hello', ' World!']

Show Python »
C:\Users\My Name>python demo_string_split.py
['Hello', ' World!']                        
                                            
                                            

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Command-line String Input

Python allows for command line input.

That means we are able to ask the user for input.

The following example asks for the user's name, then, by using the input() method, the program prints the name to the screen:

Example

demo_string_input.py

print("Enter your name:")
x = input()
print("Hello, ", x)

Save this file as demo_string_input.py, and load it through the command line:

C:\Users\Your Name>python demo_string_input.py

Our program will prompt the user for a string:

Enter your name:

The user now enters a name:

Linus

Then, the program prints it to screen with a little message:

Hello, Linus