Strings in Python

PYTHON STRINGS

By Klea h

​Strings in python are surrounded by either single quotation marks, or double quotation marks.

'hello' is the same as "hello".

You can assign a multiline string to a variable by using TRIPLE quotes.

''' Lorem ipsum dolor sit amet,

ut labore et dolore magna aliqua.'''

Multiple Choice

Which of the following is a valid way to define a string in Python?

• greeting = 'Hi there'

• greeting = "Hi there"

• greeting = '''Hi there'''

• All of the above

Multiple Choice

What is the correct way to create a multiline string in Python?

B) note = '''Line1 Line2 Line3'''
C)
D) note = "Line1 Line2 Line3"

• note = '''Line1

  Line2

  Line3'''

• note = "Line1

  Line2

  Line3"

• note = 'Line1

  Line2

  Line3'

• I have no Idea

​Square brackets can be used to access elements of the string.

The first character in Python has the position 0


a = "PYTHON"
print(a[1])


RESULT: Y

Multiple Choice

What will this print?

word = "Computer"

print(word[3])

• p

• o
• u

• C

Multiple Choice

What is the index of the first character in a string?

• 1
• -1
• It depends on the user

• 0

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

a = "Hello, World!"

print(len(a))

RESULT: 13

Multiple Choice

Which function is used to find how many characters a string has?

• length

• len()

• length()

• len

Multiple Choice

What is the output of the following code?

msg = "Good morning"

print(len(msg))

• 12
• 10
• 15
• error

​Check String

To check if a certain phrase or character is present in a string, we use the keyword in.

txt = "The best things in life are free!"

print("free" in txt)
RESULT: True

To check if a certain phrase or character is NOT present in a string, we can use the keyword not in.

txt = "The best things in life are free!"

print("expensive" not in txt)
RESULT: True

Multiple Choice

What does the following code return?

sentence = "Coding is fun!"

print("fun" in sentence)

• True
• False
• None
• Error

Multiple Choice

What will this return?

text = "Apples are red"

print("green" not in text)

• Error
• True
• None
• False

​Slicing

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

Specify the start index and the end index, separated by a colon, to return a part of the string.

b = "Computer Lab"
print(b[2:5])

RESULT: mpu

​Slice From the Start

By leaving out the start index, the range will start at the first character:
b = "Hello, World!"
print(b[:5]) -> character in index 5 is NOT included




​Slice To the End

By leaving out the end index, the range will go to the end:
b = "Hello, World!"
print(b[2:]) --> starting from the character in index 2 until the end

​Negative Indexing


Use negative indexes to start the slice from the end of the string:
From: "Y" in "World!" (position -5)
To, but not included: "O" in "World!" (position -2):

b = "PYTHON"

print(b[-5:-2])

​Python has a set of built-in methods that you can use on strings.
Note: All string methods return new values.
They do not change the original string.

The upper() method returns the string in upper case:
print(a.upper())

The lower() method returns the string in lower case:
print(a.lower())

The strip() method removes any whitespace from the beginning or the end:
print(a.strip())
# returns "Hello, World!"