String Literals
String literals in python are surrounded by either single quotation marks or double quotation marks.
'hello' is the same as "hello".
You can display a string literal with the
print() function:Example
print("Hello")
print('Hello')
Assign String to a Variable
Assigning a string to a variable is done with the variable name followed by an equal sign and the string:
Example
a = "Hello"
print(a)
Multiline Strings
You can assign a multiline string to a variable by using three quotes:
Example
You can use three double quotes:
a = """Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua."""
print(a)
Or three single quotes:
Example
a = '''Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua.'''
print(a)
Note: in the result, the line breaks are inserted at the same position as in the code.
Strings are Arrays
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])
Example
Substring. Get the characters from position 2 to position 5 (not included):
b = "Hello, World!"
print(b[2:5])
Example
The strip() method removes any whitespace from the beginning or the end:
a = " Hello, World! "
print(a.strip()) # returns "Hello, World!"
Example
The len() method returns the length of a string:
a = "Hello, World!"
print(len(a))
Example
The lower() method returns the string in lower case:
a = "Hello, World!"
print(a.lower())
Example
The upper() method returns the string in upper case:
a = "Hello, World!"
print(a.upper())
Example
The replace() method replaces a string with another string:
a = "Hello, World!"
print(a.replace("H", "J"))
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!']
Learn more about String Methods with our String Methods Reference
String Format
As we learned in the Python Variables chapter, we cannot combine strings and numbers like this:
Example
age = 36
txt = "My name is John, I am " + age
print(txt)
But we can combine strings and numbers by using the
format() method!
The
format() method takes the passed arguments, formats them, and places them in the string where the placeholders {} are:Example
Use the
format() method to insert numbers into strings:
age = 36
txt = "My name is John, and I am {}"
print(txt.format(age))
The format() method takes unlimited number of arguments, and are placed into the respective placeholders:
Example
quantity = 3
itemno = 567
price = 49.95
myorder = "I want {} pieces of item {} for {} dollars."
print(myorder.format(quantity, itemno, price))
You can use index numbers
{0} to be sure the arguments are placed in the correct placeholders:Example
quantity = 3
itemno = 567
price = 49.95
myorder = "I want to pay {2} dollars for {0} pieces of item {1}."
print(myorder.format(quantity, itemno, price))