1. Formatting Output

2. Review
We’ve run into a few problems in printing out our desired statements.
Let’s look at a few of them:
print(“$”, 3.99)
>> $ # we don’t like that unnecessary space

3. Review
We attempted to solve this problem by using concatenation with the math symbol “+”
print(“$” ) # error!
But this gave us an error, because we can’t add a string to an integer

4. Review
So then, we used the conversion functions: int( ), float( ), str( ) which allowed us to convert data into the necessary data types
print(“$” + str(3.99) )
>> $3.99
Note: The str( ) function converts data into a string.

5. Review
Now, the only problem was that when we converted certain data into strings, we were no longer to use them in our math calculations.
So, what else does Python have that might be able to help us?

6. Line Endings
By now, you’ve noticed that the print( ) function will automatically print out a new line after passing all of the arguments
Example:
print ( “one”)
print ( “two”)
>> one
two

7. Line Endings
Well now we can avoid this automatic space in between print statements by changing the ending of each print( ) function
Example:
print ( “one”, end = “” )
print ( “two”, end = “”)
>> onetwo

8. Line Endings
It turns out, you can actually ask the print function to add whatever you’d like at the end of it’s execution
print (“one”, end = “***” )
print (“two”, end = “ ” )
print (“three”, end = “ (: ” )
>> one***two three (:

9. But why?
This may not seem very helpful at the moment but later on, we will use this in our loops because it allow us to keep all of our printed data on one line as the user continues to input it

10. Separating Arguments print (“$”, 3.99) >> $ 3.99
By now, you should’ve also noticed that the print function prints a space in between each argument that is passed through it
print (“$”, 3.99)
>> $ 3.99

11. Separating Arguments print (“$”, 3.99, sep = “” ) >> $3.99
This can also be avoided as well by a separator specific command in the print function
Example:
print (“$”, 3.99, sep = “” )
>> $3.99

12. Separating Arguments print (“one”, “two”, sep = “” ) >> onetwo
Notice though, that you must use a comma to separate the given arguments and the final separator command
Example:
print (“one”, “two”, sep = “” )
>> onetwo

13. Separating Arguments
You guessed it, you can also separate arguments however you’d like.
More Examples:
print (“hello world”, “!”, “?”, sep = “” )
>> hello world!?
print (“one”, “two”, “three”, sep = “*” )
>> one*two*three

14. Combination
You can also combine these commands into a single print( ) function
Example:
print (“a”, “b”, “c”, sep = “**”, end = “$” )
print (“d”, “e”, “f”, sep = “-”, end = “” )
>> a**b**c$d-e-f
The order does not matter

15. Tab Command
Another escape command is the tab command and it is denoted by “ \t ”
This must be added inside a string
A tab is the equivalent of 8 blank spaces

16. Tab Command
Example: print (“First\t”, “Second\t”, “Third”) print (“10.9\t”, “11.2\t”, “11.4”) >> First Second Third

17. Tab Command
Keep in mind, the escape commands are considered strings so you cannot add them to the end of a variable. You must create a new argument as a string.
name = input(“What’s your name?”)
print( name\t )
# this will cause an error

18. Tab Command
Correct way name = input(“What’s your name?”) print( name, “\t”, “is the best!” ) >> What’s your name? Donald Donald is the best!

19. Reminder
Remember that something to keep in mind: Python spaces each character the same, regardless of actual character width
Example:
“hello”
“WQWQW”
“I I I”
Note: These all have the same string width in Python

20. 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

21. 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

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

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

30. 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

31. 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)
>>

32. 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

33. 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

34. 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

35. 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

36. 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

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

38. 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

39. 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

40. 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

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