strings.md

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Strings

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

'hello' is the same as "hello".

Assign String to a Variable

a = "Hello"

Multiline Strings

a = """Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua."""

or

a = '''Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua.'''

Strings are Arrays

Like many other popular programming languages, strings in Python are arrays of bytes representing unicode characters.

a = "Hello, World!"
print(a[1])
Output: e

Slicing

You can return a range of characters by using the slice syntax.

b = "Hello, World!"
print(b[2:5])
Output: llo

Negative Indexing

Use negative indexes to start the slice from the end of the string.

b = "Hello, World!"
print(b[-5:-2])
Output: orl

String Length

To get the length of a string, use the len() function.

a = "Hello, World!"
print(len(a))
Output: 13

Other Methods

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

a = " Hello, World! "
print(a.strip())
Output: "Hello, World!"

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

a = "Hello, World!"
print(a.lower())

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

a = "Hello, World!"
print(a.upper()) 

The swapcase() method returns the string with swap upper and lower case:

a = "Hello, World!"
print(a.upper()) 

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

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

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

a = "Hello, World!"
print(a.split(","))
Output: ['Hello', ' World!'] 

Check if the phrase "ain" is present in the following text:

txt = "The rain in Spain stays mainly in the plain"
x = "ain" in txt
print(x)
Output: True

Check if the phrase "ain" is NOT present in the following text:

txt = "The rain in Spain stays mainly in the plain"
x = "ain" not in txt
print(x) 
Output: False

To concatenate, or combine, two strings you can use the + operator.

a = "Hello"
b = "World"
c = a + b
print(c)
Output: HelloWorld

To add a space between them, add a " ":

a = "Hello"
b = "World"
c = a + " " + b
print(c)
Output: Hello World