6 Manipulating Strings

Question 1

What are escape characters?

Answer 1

They let yo use characters that are otherwise impossible to use in a string, e.g.:

\t Tab
\n Newline (line break)
\ Backslash

Question 2

How do you indicate a raw string? What does it do?

Answer 2

> > > print(r’That is Carol's cat.’)
That is Carol's cat.

It ignores all excape characters and prints any backslahs used in the string

Question 3

What areTriple Quotes useful for?

Answer 3

E.g. for multiline strings or multiline comments.

Also you don´t need escape characters like \n for a new line

Question 4

How do string interpolation/ the modulo operator work?

Answer 4

> > > name = ‘Al’
age = 4000
‘My name is %s. I am %s years old.’ % (name, age)
‘My name is Al. I am 4000 years old.’

In the modulo operator the %s operator inside the string acts as a marker to be replaced by values following the string.

Question 5

What is a benefit of the modulo operator?

Answer 5

It requires less time & typing

Also, values (e.g. integers) don´t have to be converted to string

Question 6

What is the f´string

Answer 6

> > > name = ‘Al’
age = 4000
f’My name is {name}. Next year I will be {age + 1}.’
‘My name is Al. Next year I will be 4001.’

It is similar to the modulo operator, just using{} instead of the %s. Also, it is indicated by an f’ at the beginning of a string.

Question 7

Name 4 useful string mehods

Answer 7

spam. upper()
spam. lower()
spam. isupper()
spam. islower()

Question 8

What do .isupper() / .islower() do?

Answer 8

They return boolean values:
True
False

Question 9

The isX() Methods 5x

Answer 9

isalpha() Returns True if the string consists only of letters

isalnum() Returns True if the string consists only of letters and numbers

isdecimal() Returns True if the string consists only of numeric characters
isspace() Returns True if the string consists only of spaces, tabs, and newlines

istitle() Returns True if the string consists only of words that begin with an uppercase letter followed by only lowercase letters

Question 10

Further useful methos

Answer 10

startswith()
endswith()
‘Hello, world!’.startswith(‘Hello’)

join() -> ‘, ‘.join([‘cats’, ‘rats’, ‘bats’])
split() -> ‘My name is Simon’.split()

Question 11

How can you keep asking someone to enter a password until he enters one only consisting of numbers and letters?

Answer 11

while True:
    print('Please enter your password.')
    password = input()
    if password.isalnum():
        break
    print('Password must consist of letters and numbers only')

Question 12

Name 3x Text-Justify methods. What values go into the bracket?

Answer 12

justify(nrSpaces, ‘fillerCharacter’):

rjust()
ljust()
center()

Question 13

How can you make this string appear 10 spaces to the right, with the filler spaces being ‘+’?

spam = ‘Hello’

Answer 13

spam.rjust(10, ‘+’)

‘+++++Hello’