Computer Science Signs, Words, Symbols, Methods, and Types

Vocabulary flashcards covering core Python signs, keywords, syntax symbols, list and random methods, and data types from the lecture notes.

+

Add numbers, or join two strings ('a' + 'b' is 'ab').

–

Subtract.

*

Multiply, or repeat a string ('ab' * 3 is 'ababab').

/

Divide; always gives a decimal (7 / 2 is 3.5).

//

Divide and drop the remainder (7 // 2 is 3).

%

The remainder (7 % 2 is 1).

**

To the power of (3 ** 2 is 9).

=

Assign: store a value in a variable (x = 5).

==

Is equal to; compares two things and gives True or False.

!=

Is NOT equal to.

<

Less than.

>

Greater than.

Less than or equal to.

=

Greater than or equal to.

+=

Add to the variable (total += 2 means total = total + 2).

and

Both sides must be True.

or

At least one side must be True.

not

Flips True to False and False to True.

in

Is it inside? (3 in [1, 2, 3] is True).

def

Define a function.

return

Send a value back to where the function was called, and end the function.

print

Show something on the screen.

input()

Ask the user to type something; always gives back a string.

if

Run the indented code only when the condition is True.

elif

'Else if': checked only if the earlier conditions were False.

else

Runs when none of the earlier conditions were True.

for

Loop: repeat the indented code for each item.

range()

Makes a sequence of numbers; stops BEFORE the last number.

len()

How many items (or characters) there are.

import random

Load the random tools so you can use random.randint and others.

: (colon at the end of a line)

An indented block starts on the next line (after if, for, def).

Indentation

The indented lines belong to the if, for, or def above them.

[ ]

[1, 2, 3] makes a list; nums[0] gets the item at position 0.

-1 (in nums[-1])

The last item in the list.

( )

Function call: the inputs (print(5)); math: do this first; condition: group it.

f'…{x}…'

An f-string: puts the value of x into the text.

:.2f (inside an f-string)

Show the number as a decimal rounded to 2 places.

#

A comment; Python ignores the rest of the line.

append

Adds an item to the end of the list.

pop(i)

Removes the item at position i AND returns it.

insert(i, x)

Puts x at position i; the others shift right.

random.randint(a, b)

Gives a random whole number from a to b, including both ends.

random.choice(list)

Picks one item from the list at random.

int, float, str, and bool

int = whole number (5); float = decimal (5.0); str = text ('5'); bool = True or False.

int(), float(), and str()

Convert a value to that type (int(3.9) is 3; float(2) is 2.0; str(5) is '5').