Output

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Outputting a string

The print command is used to output a character or string to the user. An example print command can be seen below.

print("Hello world!")

The syntax rules for the basic print statement are:

Combining strings and values stored in variables

There are three key methods you can use to join strings and values stored in variables: string printing, concatenation and f-strings. I generally tend to use f-strings because of their advantages but it is important to know the other methods so you can understand other people's code.

String printing

This method only works in print statements. The other two can be used with input statements as well. With string printing, a comma separates each variable and string. When a comma is used the two items are joined and a space is inserted automatically between them. An example of string printing can be seen below.



The syntax rules for string printing are:

Benefits of string printing

It doesn't matter what data type is stored as in a variable, the string version of this will be printed.
Drawbacks of string printing

A space is always inserted between strings and values in variables whether you want one or not
Cannot be used in the prompt in input statements

Concatenation

Concatenation is a method that can be used to join strings together. Because it only joins strings, other types of variables must be cast to use them like this. Any spaces to be included must be written inside strings.



The syntax rules for concatenation are:

Benefits of concatenation

No spaces are inserted automatically
Can be used in the prompt to an input command
Drawbacks of concatenation

You have to remember to cast non-string variables
Spaces must be added inside strings and can be easily forgotten or misplaced

F-strings

F-strings have been adopted from other programming languages. When we use f-strings there will always be one set of speech marks in a print statement that surround everything to be printed. These speech marks are preceded by a lower-case f. Values being retrieved from variables are written in braces(i.e. curly brackets { }). This method always prints the string version of variables so no casting is required.



The syntax rules for f-strings are:

Benefits of string printing

It doesn’t matter what data type is stored in a variable, the string version of this will be printed
Spaces will be exactly as typed
Can be used in the prompt to an input statement
There are a range of easy tools to use with f-strings to deal with layout

Syntax checker

String printing

Copy the lines below into a Python editor of your choice. Each line has a one or more syntax errors. Fix them one by one so they use string printing to output the desired sentence.

name = "Bob"
age = 32
height = 1.67
print("name", is, "age") #should output: Bob is 32
Print("My name is", name) #should output: My name is Bob
print("name is age") #should output: Bob is 32
print(name, "is" height, "meters tall") #should output: Bob is 1.67 meters tall
print(name, " is ", age, " years old.") #should output: Bob is 32 years old



name = "Bob"
age = 32
height = 1.67
print(name, "is", age) #Speech marks now around string not variables
print("My name is", name) #print now in lowercase
print(name, "is", age) #speech marks removed from whole output sentence and placed just around strings
print(name, "is", height, "meters tall") #second comma added to join string to height
print(name, "is", age, "years old.") #additional spaces removed

Concatenation

Copy the lines below into a Python editor of your choice. Each line has a one or more syntax errors. Fix them one by one so they use string printing to output the desired sentence.

name = "Bob"
age = 32
height = 1.67
print(name + " is " + age) #should output: Bob is 32
Print("My name is" + name) #should output: My name is Bob
print(name + " is " + str(age) #should output: Bob is 32
print(name + " is " height + "m tall") #should output: Bob is 1.67m tall
print("name + is + str(age)") #should output: Bob is 32



name = "Bob"
age = 32
height = 1.67
print(name + " is " + str(age)) #age cast as string
print("My name is " + name) #print now in lowercase and space added inside string
print(name + " is " + str(age)) #final missing bracket added
print(name + " is " + str(height) + "m tall") #second plus added to join string to height and height cast as string
print(name + " is " + str(age)) #variables no longer inside the speech marks

F-strings

Copy the lines below into a Python editor of your choice. Each line has a one or more syntax errors. Fix them one by one so they use f-strings to output the desired sentence.

name = "Bob"
age = 32
height = 1.67
print("{name} is {age}") #should output: Bob is 32
Print(f"My name is" {name}) #should output: My name is Bob
print(f"(name) is (age)") #should output: Bob is 32
print(f{name} is {height}m tall) #should output: Bob is 1.67m tall
print(f{name} "is" {age} "years old") #should output: Bob is 32 years old



name = "Bob"
age = 32
height = 1.67
print(f"{name} is {age}") #f added at start of string
print(f"My name is {name}") #print now in lowercase and name is inside the string
print(f"{name} is {age}")) #round brackets swapped for braces
print(f"{name} is {height}m tall") #missing speech marks added
print(f"{name} is {age} years old") #one set of speech marks surround everything to be printed

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