Using Bad Versus Good Variables and Function Names

Compare the two programs below:

Example 1: The programmer has chosen to use poor variable names.

def main():

# Open the sales.txt file for reading.

s = open('sales.txt', 'r')

# Read all the lines from the file.

for l in s:

# Convert line to a float.

a = float(l)

# Format and display the amount.

print(format(a, '.2f'))

# Close the file.

s.close()

# Call the main function.

main()

Example 2: The programmer has chosen to use good variable names.

def main():

# Open the sales.txt file for reading.

sales_file_in = open('sales.txt', 'r')

# Read all the lines from the file.

for i in sales_file_in:

# Convert line to a float.

number = float(i)

# Format and display the amount.

print(format(number, '.2f'))

# Close the file.

sales_file_in.close()

# Call the main function.

main()

In example 2 above, the variable names are descriptive of the information they hold, such as " sales_file_in" will hold data from the "sales.txt" file. Also, notice the poor choice of variables in Example 1 on line 6. " for l in s:" As you can see, it is difficult if not impossible to tell that is the variable lower case "L". Will likely lead to much confusion.