Strings

Question 1

Stings

Answer 1

Strings are ordered sequences of characters, using the syntax of either single quotes or double quotes:

• ‘hello’
• “hello”
• ” I don’t do that “

Question 2

Indexing

Answer 2

Grabbing a single character from a string [use brackets]. Python indexing starts at 0.
h e l l o
0 1 2 3 4

Question 3

Reverse Indexing

Answer 3

Same as indexing but backwards
h e l l o
0 1 2 3 4
0 -4 -3 -2 -1

Question 4

Slicing

Answer 4

Allows you grab a subsection of multiple characters
[start:stop:step]
Start - a numerical index from the slice start
Stop - the index you will go up to (but not include)
Step - the size of the “jump” you take

Question 5

” “

Answer 5

Denotes a string. Used for a string with a contraction word i.e. “I don’t think so”

Question 6

Escape Sequence

Answer 6

\n = new line
print(‘hello \n world’)
hello
world

\t = tab space
print(‘hello \tworld’)
hello world

Question 7

Length Function Len()

Answer 7

Len(‘hello’)
5
Len(‘I am)
4

Question 8

Indexing

Answer 8

mystring = “Hello World”
mystring[0]
H

mystring[2:] #from this character onward
mystring[:3] #go up to that position, but do not include that character

Question 9

Slicing

Answer 9

[start:stop:step]
mystring[3:6]
mystring[::-1] #Easy trick to reverse a string!!

Question 10

Slicing is Immutable. True or False?

Answer 10

True

Question 11

Slicing is immutable. What does that mean?

Answer 11

Once a string is defined it cannot be sliced to redefine part of it.

name = "Sam"
name[0] = 'P'    #This will give an error because 'str' object does not support item assignment

Question 12

String Concatination

Answer 12

Adding strings together

x = ‘Hello World’
x + “ it is beautiful outside!”
‘Hello World it is beautiful outside!

letter = ‘z’
letter * 10
‘zzzzzzzzzz’

Question 13

You can concatinate a number and a string? True or False?

Answer 13

False

Question 14

Strings are mutable. True or False?

Answer 14

False

Question 15

How do you create comments in your code?

Answer 15

#

Question 16

String Interpolation

Answer 16

Fancy way of saying: injecting variables into a string.

my_name = “Jose”
print(“Hello” + my_name)

Question 17

.format method

Answer 17

Method for doing string interpolation

print(“The result was {r:1.5f}”.format(r = result))
The result was 0.12870

Question 18

Float Formatting

Answer 18

“{value:width.precision f}”
r : 1 . 5 f
print(“The result was {r:1.5f}”.format(r = result))
The result was 0.12870

Question 19

f string method (aka formatted strings literal)

Answer 19

Quick way of doing string interpolation.

name = “Jose”
age = “3”
print(f’{name} is {age} years old.’)
Jose is 3 years old.