Writing Clear Code

Appendix D: Python Programming Cheatsheet

This appendix summarizes the most commonly-used Python language features in the textbook.

Hello, World.

import stdio

# Write 'Hello, World' to standard output.
stdio.writeln('Hello, World')

Editing, compiling, and interpreting.

Built-in data types.

Assignment statements and traces.

Strings.

Integers.

Floating-point numbers.

Booleans.

Comparison operators.

Common functions.

Type conversion.

`if` and `if-else` statements.

`if-elif-else` statements.

if   income < 0:      rate = 0.00
elif income < 8925:   rate = 0.10
elif income < 36250:  rate = 0.15
elif income < 87850:  rate = 0.23
elif income < 183250: rate = 0.28
elif income < 398350: rate = 0.33
elif income < 400000: rate = 0.35
else:                 rate = 0.396

`while` and `for` statements.

`break` statements.

while True:
    x = 1.0 + 2.0*random.random()
    y = 1.0 + 2.0*random.random()
    if x*x + y*y <= 1.0:
        break

Arrays.

suits = ['Clubs', 'Diamonds', 'Hearts', 'Spades']

a = stdarray.create1D(n)
...
for i in range(n):
    stdout.writeln(a[i])
... 
for element in a:
    stdout.writeln(element)

Array operations.

Array aliasing and copying.

Two-dimensional arrays.

a = stdarray.create2D(rowCount, colCount)
...
for i in range(rowCount):
    for j in range(colCount)):
        stdio.writeln(a[i][j])
...     
for row in a:
    for element in row:
        stdio.writeln(element)