Style Point Deductions Starting in HW5

Remember there are "official" Python Style guidelines you can refer to here for more detail. This list is meant to be a quick reminder of specific issues we have seen in homeworks this quarter.

Variable and function naming.

Students shouldn't use single letter names for variables that should really be 'factorial', 'current_sum', or 'reciprocal'. n, i, and j are fine for loop variables.

• You should use descriptive variable names, such as "factorial" or "current_sum", that describe the value the variable contains.

• In Python, it’s recommended to name variables and functions in a certain way so that other Python programmers can read your code more easily. Here are some examples of variable names: "num_lines", "triangular_number", "running_sum", "my_friends", etc. Note: Other programming languages (e.g. Java) have different conventions for naming. Use the conventions of the language you are working in.

Space between a function and its parameter list.

• You should write, for example, "range(x)" instead of "range (x)" (in other words, you should remove the space). Using the space suggests--incorrectly--that the parenthesis are for grouping an expression, when in fact they are for calling the function.

Spaces around operators.

• It’s recommended that you put spaces around binary operators such as +, -, /, *, and **. This makes the code easier to read in most cases.

• It’s recommended that you put spaces around comparisons such as <, <=, >, >=, and ==. This makes the code easier to read in most cases.

Lingering debug code.

• Please remove any print statements or unnecessary computations that you added to help debug errors before you turn in your program. Don't just leave unnecessary code commented out. It makes the real code harder to read.

Unnecessary nested if statements or a series of if statements

• Avoid nesting if statements that can be written as one if statement.

Do this:

if val > 120:
    print "Green!"
 
elif val > 80:
    print "Blue!"
 
elif val > 32:
    print "Red!"
 
else:
    print "Orange!"

Instead of this:

if val > 120:
    print "Green!"
 
else:
    if val > 80:
        print "Blue!"
 
    else:
        if val > 32:
            print "Red!"
 
        else:
            print "Orange!"

• If the intent is for only one block of code to execute, be sure to use if, elif, else instead of a series of ifs.

Do this:

for base in nucleotides:
    if base == 'A':
        # code here 
 
    elif base == 'C':
        # code here 
 
    elif base == 'T':
        # code here 
 
    elif base == 'G':
        # code here 

Instead of this:

for base in nucleotides:
    if base == 'A':
        # code here 
 
    if base == 'C':
        # code here 
 
    if base == 'T':
        # code here 
 
    if base == 'G':
        # code here 

Looping over the same data multiple times in a row

• Avoid repeated for loops if you can perform all the operations inside one loop.

Do this:

for base in nucleotides:
    if base == 'A':
        # code here 
 
    elif base == 'C':
        # code here 
 
    elif base == 'T':
        # code here 
 
    elif base == 'G':
        # code here 

Instead of this:

for base in nucleotides:
    if base == 'A':
        # code here 
 
for base in nucleotides:
    if base == 'C':
        # code here 
 
for base in nucleotides:
    if base == 'T':
        # code here 
 
for base in nucleotides:
    if base == 'G':
        # code here 

Replicating code from functions that you already wrote

• Don't write the same code again if you already have a function that performs that action. Just call the function.

• Perhaps two similar but not identical pieces of code can be turned into a function by using parameters.

Comenting and docstrings

• Be sure to include a docstring for each function.

• Include other comments (with #) inside of the function to describe what you are doing. Be sure to add comments to tricky parts of code. However do avoid unecessary comments (e.g. # increment count) which should be obvious from looking at the code.