Interactive Python: Strings

Front 1

Strings are made up of smaller strings, each containing one ___

Back 1

character

Front 2

types comprised of smaller pieces are called

Back 2

collection data types

Front 3

a string that contains no characters is called an

Back 3

empty string

Front 4

what's the indexing operator?

What is the index?

Back 4

[] indexing operator

the index is the number inside the indexing operator ex. [4]

Front 5

give the index of the characters in the following string from left to right and right to left:

"Python"

Back 5

left to right: 0, 1, 2, 3, 4, 5

right to left: -1, -2, -3, -4, -5, -6

Front 6

the index of the first character of a string is which number? what about the last character of a string?

Back 6

first: 0

last: -1

Front 7

what's the general format for a statement that performs a method on an object?

Back 7

object.method(value)

Front 8

is a string an object? if so is it mutable or immutable? (changable or unchangable?)

Back 8

A string is an immutable object - it cannot be changed.

Front 9

Make a statement to print out the string "table" in all caps.

Back 9

print("table".upper())

Front 10

Make a statement to print out the string "Blue" in all lowercase

Back 10

print("Blue".lower())

Front 11

How print the length of a string?

Back 11

print(len("string"))

Front 12

Which error will this return? why?

print("fruit"[len("fruit")])

How can you fix it so that it will print the last character of the string (assuming you don't know the length of the string beforehand?)

Back 12

"IndexError: string index out of range"

len("fruit") returns the length of the string "fruit" starting at 1, so len("fruit") returns 5. But with indexing, the counting starts at 0, so the index of the characters of "fruit" only go up to 4 (t is index of 4). So you try to print "fruit"[5] which doesn't exist.

fixed version:

print("fruit"[len("fruit") - 1])

Front 13

What is the slice operator?

What does it do?

Give an example using it.

Back 13

[:]

the slice operator is the :

It returns a part of a string starting from the index to the left of the colon up to but excluding the index to the right of the colon.

Example: "computer"[4:7] returns ute (the characters at indexes 4, 5, and 6)

Front 14

for the string "computer" write a statement to return the following, using the slice operator for each:

ute

uter

comp

computer

Back 14

"computer"[4:7]

"computer"[4:]

"computer"[:4]

"computer"[:]

Front 15

What is lexicographical order?

Back 15

like alphabetical order except capital letters come before lowercase ex ABCDEabcde

THE LETTERS THAT COME FIRST HAVE A LOWER VALUE such that A < a and d > c

Front 16

What do the following return:

"apple" < "banana"

"zebra" < "apple"

"Zebra" < "apple"

"Zebra" > "zebra"

"Zebra" == "zebra"

"Zebrafish" > "z"

How are these strings being compared?

Back 16

True

False

True

False

False

False

the ordinal value of the FIRST character of the string(???) (which is assigned by lexicographical order) is being compared.

Front 17

HOw is the ordinal value of a character determined?

Back 17

by its lexicographical order.

Front 18

How do you find out the ordinal value of a character? (write a statement)

Back 18

ord("a")

a is random character

Front 19

How do you find out which character is assigned to a certain ordinal value?

Back 19

chr(52)

52 is the ordinal value

Front 20

Does the space character have an ordinal value?

Back 20

yes! it is 32

Front 21

Are strings mutable?

Back 21

NO! STRINGS ARE IMMUTABLE

Front 22

HOw use the range function to print 0 through 9? write the statement.

Back 22

for i in range(10):

print(i)

Front 23

a string is a sequence of...

Back 23

characters

Front 24

Write a statement to:

iterate over the char in "apple" and print each character, using the index of each character. pretend you don't know how many characters are in "apple"

Back 24

for i in range(len("apple")):

print "apple"[i]

Front 25

Write a statement to:

iterate over and print the first two characters of "apple", using the index of each character. pretend you don't know how many characters are in "apple"

Back 25

for i in range(len("apple") - (len("apple") - 2)):
print "apple"[i]

Front 26

How many times is the letter o printed by this statement?

Back 26

2

Front 27

Write a while loop to interate over the string "apple" and print every character. pretend you don't know how many characters are in "apple"

Back 27

position = 0

while position < len("apple"):

print "apple"[position]

position += 1

Front 28

How many times is the letter o printed by this statement?

how many times is p printed?

Back 28

0, 0

Front 29

print('p' in 'apple')

What does this print?

Back 29

True

Front 30

print('i' in 'apple')

What does this print?

Back 30

False

Front 31

print('' in 'apple')

What does this print?

Back 31

True (an empty string is a substring of any string)

Front 32

print('a' not in 'apple')

What does this print?

Back 32

False

Front 33

print('i' not in 'apple')

What does this print?

Back 33

True

Front 34

What is printed by the following?

s = "ball"

r = ""

for item in s:

r = item.upper() + r

print(r)

Back 34

LLAB

because of the way it's concatenated with the iterated item first

Front 35

write a function counting the letters of a string input as a parameter

Back 35

def count(string):

charcount = 0

for i in string:

charcount += 1

return charcount

Front 36

In the beginning of the function find3 written below, how can we rewrite it to make the parameter start have a default function of 0 (if the parameter isn't specified when the function is called?)

def find3(astring, achar, start)

Back 36

def find3(astring, achar, start=0)

Front 37

In the beginning of the function find3 written below, how can we rewrite it to make the parameter end optional - that is, assign the parameter no value at all if it is not entered when the function is called?

def find3(astring, achar, start, end)

Back 37

def find3(astring, achar, start, end=None)

Front 38

What is printed?

import string

print(string.ascii_lowercase)

Back 38

abcdefghijklmnopqrstuvwxyz

Front 39

What is printed?

import string

print(string.ascii_uppercase)

Back 39

ABCDEFGHIJKLMNOPQRSTUVWXYZ

Front 40

What is printed?

import string

print(string.digits)

Back 40

0123456789

Front 41

What is printed?

import string

print(string.punctuation)

Back 41

!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~

Front 42

You do ____ to access a single character in a string using its position (starting from 0).

Write the operator, and Give an example

Back 42

indexing[]

Example: 'This'[2] evaluates to'i'.

Front 43

____ returns the number of characters in a string.

Write the operator, and give an example.

Back 43

len(string)

Example: len('happy') evaluates to 5.

Front 44

______ a string (with a ___ _____) means accessing each character in the string, one at a time.

Give an example.

Back 44

traversing (with a for loop)

For example, the following for loop:

for ix in 'Example':

Front 45

A ____ is a substring of a string.

Write the operator.

Give an example:

Back 45

slice (or slicing)

[:]

'bananas and cream'[3:6] evaluates to ana (so does'bananas and cream'[1:4]).

Front 46

The six common comparision operators work with strings, evaluating according to _____ order.

Back 46

lexigraphical

Front 47

The _____ operator tests whether one string is contained inside another string.

Back 47

in

Front 48

define: collection data type

Back 48

A data type in which the values are made up of components, or elements, that are themselves values.

Front 49

define:

default value

Back 49

The value given to an optional parameter if no argument for it is provided in the function call.

Front 50

define:

dot notation

Back 50

Use of the dot operator, ., to access functions inside a module, or to access methods and attributes of an object.

Front 51

define:

immutable

Back 51

A compound data type whose elements can not be assigned new values.

Front 52

define:

index

Back 52

A variable or value used to select a member of an ordered collection, such as a character from a string, or an element from a list.

Front 53

define:

optional parameter

Back 53

A parameter written in a function header with an assignment to a default value which it will receive if no corresponding argument is given for it in the function call.

Front 54

define:

slice

Back 54

A part of a string (substring) specified by a range of indices. More generally, a subsequence of any sequence type in Python can be created using the slice operator (sequence[start:stop]).

Front 55

define:

traverse

Back 55

To iterate through the elements of a collection, performing a similar operation on each.

Front 56

define:

whitespace

Back 56

Any of the characters that move the cursor without printing visible characters. The constantstring.whitespace contains all the white-space characters.

Front 57

in lexicographical order, capital letters come __ (before/afte) lowercase letters and so have a ____ (lower, higher) value

Back 57

BEFORE, LOWER

Front 58

How do you find the index of a substring within a string? (a very quick method can do this)

Back 58

string.find(substring)

ex.

"string".find("ng")

evaluates to

4