Cs 150 - Midterm "Cheat Sheet" printable pdf download

CS 150 - Midterm “Cheat Sheet”

Input/Output

• Reading input from the user

input(message):

Displays message to the user and returns what the user typed as a string

• Reading from a file

file = open(filename, "r")

for line in file:

# do something with line (a string)

file.close()

Strings

• The following functions are built-in and answer questions about strings

len(string):

Returns the number of characters in the string

int(string), float(string):

Converts a string to an int or float

• String object methods

upper(), lower(), capitalize():

Returns a new string that is upper or lower-cased, or capitalized

find(some_string):

Returns the index that some_string occurs at in the string or -1 if it does not occur

find(some_string, index):

Same as above, but starts searching at index

replace(old, new):

Return a copy of the string with all occurrences of old substituted with new

startswith(prefix):

Returns True if the string starts with prefix, False otherwise

endswith(suffix):

Returns True if the string ends with suffix, False otherwise

strip():

Returns a copy of the string with leading and trailing whitespace removed

split():

Return a list of the words in the string using a space as the delimiter

• String operators

string1 + string2:

Returns a new string that is the concatenation of string1 and string2

string * int:

Returns a new string that is string repeated int times

Lists

• The following functions are built-in and answer questions about lists

len(list):

Returns the number of elements in list

sum(list), min(list), max(list):

Returns the sum, min, or max of elements in list

• List object methods

append(x):

Adds x to the end of the list

insert(index, x):

Insert x at index in the list

pop():

Removes the item at the end of the list and returns it

pop(index):

Removes item at index from the list and returns it

reverse():

Reverses the elements in the list

sort():

sorts the elements in the list

• List operators

list1 + list2:

Returns a new list that contains the elements of list1 followed by the elements of list2

list * int:

Returns a new list that contains the items in list repeated int times

Modules

•

turtle

module

forward(distance):

Move the turtle forward by the specified distance

right(angle) left(angle):

Turn the turtle right/left by angle

goto(x, y):

Move turtle to position x, y

setheading(angle):

Set the turtles heading to angle

circle(radius):

Draw a circle with specified radius; the center is radius units left of the turtle

penup():

Pull the pen up – no drawing when moving

pendown():

Put the pen down – drawing when moving

fillcolor(color):

Change the fill color to color, where color is a string

begin_fill():

Start filling

end_fill():

Fill in the shape drawn since the last call to

begin_fill

•

random

module

randint(a, b):

Return a random integer N such that a ≤ N ≤ b

uniform(a, b):

Return a random floating point number N such that a ≤ N ≤ b

•

math

module

sqrt(num):

Return the square root of num

Cs 150 - Midterm "Cheat Sheet"

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