1. Formatting Output

2. Programming Challenge
Write a program that asks the user for three cars, three different interest rates, and three prices
Print an output like this:
Car Name Interest Rate Price
BMW % $ 79,435.60
Mercedes Benz 4.2% $ 119,324.54
Bentley % $234,674.93

3. The Inefficiency of the TAB Command
The TAB command is inefficient and you should NEVER, or almost never use it to format in Python
Because …

4. Formatting a String Python also has a format( ) command
This command allows you to format a string and returns it as a new piece of data
This can be done in a variable or directly in the print function

5. Formatting a String The format( ) function accepts two arguments
The first argument is the piece of data you want to format (we will work with strings first)
The second argument is the formatting pattern you would like it to follow

6. Formatting a String
One common pattern of formatting is to ensure that a string has a known number of characters
For example, let’s say you want your output to look like this:
Name Class
Donald Seok Computer Programming
Drake Rapping 101

7. Formatting a String Name Class Donald Seok Computer Programming
You’ll need the strings “Name” and “Donald Seok” to have the same number of characters in them so that the strings “Class” and “Computer Programming” will align perfectly after them

8. Formatting a String
We can achieve this task by adding extra spaces to either the beginning or the end of a string
x = format (“Name”, “<20s”)
This generates a string with 20 characters, which means Python will add 16 spaces after the 4 characters in the word “Name”
The “<” character means left justify the string and place extra spaces at the “end” of the new string

9. Formatting a String
You guessed it … you can also tell Python to right justify the string and add spaces to the beginning of the string
Example:
x = format (“Name”, “>20s”)
print (x)
>> Name
^ 16 blank characters

10. Formatting a String So, let’s try making that output:
word_name = format (“Name”, “<20s”)
my_name = format(“Donald Seok”, “<20s”)
print ( word_name , “Class”, sep = “” )
print ( my_name , “Computer Programming”, sep = “” )
>> Name Class
Donald Seok Computer Programming

11. Formatting a String
You can also add a character in front of the instruction set to tell Python to add that character as many times as it needs in order to fulfill the total number of characters in the string
The default is a blank space

12. Formatting a String
x = format (“Name”, “>20s”) print (x) >> Name x = format (“Name”, “*>20s”) >> ****************Name

13. Formatting Numbers The format( ) command also works on numbers
However, it is important to keep in mind that the number, whether integer or float, will be returned as a string from the function

14. Formatting Numbers
This command would’ve come in handy when we were writing programs that printed out prices
This is what we’re used to seeing:
a = 1 / 3
print (a)
>>

15. Formatting Numbers Now, using the format function: a = 1 / 3
b = format ( a , “.2f” )
print (b)
>> 0.33
#The number denotes the number of characters you would like to remain after the decimal point

16. Formatting Patterns
a = / 6 print ( format( a, “.3f” ) ) # 3 digits after “.” >> print ( format( a, “,.3f” ) ) # 3 digits and commas >> 16, print ( format( a, “>20,.3f” ) ) # 3 digits, commas and 20 >> 16, characters, right justified

17. Formatting Numbers There’s a lot of these instruction sets.
Also, you may need to play around with the order of these instruction sets because the format of the characters is not always completely straight forward

18. Formatting Percentages
The “%” sign converts a number into a percentage by multiplying it by 100 and then adding the “%” symbol
a = 0.52
print ( format( a, “ % ” ) )
>> %
print ( format( a, “ .2% ” ) ) # percentage with 2 digits
>> % after decimal point

19. Formatting Integer
We can also add commas after each group of three digits
The letter “d” is not necessary but denotes decimal notation
print ( format( 20000, “ ,d ” ) )
>> 20,000
print ( format( , “ >20, ” ) )
>> ,000

20. Formatting Numbers
The letter “b” converts a number into binary notation
x = format(137, “b”)
print(x)
>>

21. Formatting Numbers
This can be useful later on, but the letter “c” converts a number in decimal notation into it’s character from the UNICODE table
print( format(68, “c”), format(69, “c”) , sep = “” )
>> DE

22. Formatting Numbers x = format(15647, “x”) print(x) >> 3d1f
For those of you interested in this kind of thing, the letter “x” actually converts a number into hexadecimal notation
x = format(15647, “x”)
print(x)
>> 3d1f

23. Programming Challenge
Try this one again, but with the format( ) function
Print an output like this:
Car Name Interest Rate Price
BMW % $ 79,435.60
Mercedes Benz 4.2% $ 119,324.54
Bentley % $234,674.93

24. Programming Challenge
Ask the user for four different numbers and then try getting an output like this:
Decimal Binary UNICODE A B C D