Python String Continued

 

Strings

Strings in python are surrounded by either single quotation marks, or double quotation marks.

'hello' is the same as "hello".

You can display a string literal with the print() function:

#You can use double or single quotes:

print("Hello")

print('Hello')

Assign String to a Variable

Assigning a string to a variable is done with the variable name followed by an equal sign and the string:

a = "Hello"
print(a)

Multiline Strings

You can assign a multiline string to a variable by using three quotes:

You can use three double quotes:

a = """Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua."""
print(a)

Or three single quotes:

a = '''Lorem ipsum dolor sit amet,
consectetur adipiscing elit,
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua.'''
print(a)

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Booleans represent one of two values: True or False.

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Boolean Values

In programming you often need to know if an expression is True or False.

You can evaluate any expression in Python, and get one of two answers, True or False.

When you compare two values, the expression is evaluated and Python returns the Boolean answer:

print(10 > 9)

print(10 == 9)

print(10 < 9)

When you run a condition in an if statement, Python returns True or False:

Print a message based on whether the condition is True or False:

a = 200
b = 33

if b > a:
  print("b is greater than a")
else:
  print("b is not greater than a")

Evaluate Values and Variables

The bool() function allows you to evaluate any value, and give you True or False in return,

Evaluate a string and a number:

print(bool("Hello"))
print(bool(15))

Example

Evaluate two variables:

x = "Hello"
y = 15

print(bool(x))
print(bool(y))

Most Values are True

Almost any value is evaluated to True if it has some sort of content.

Any string is True, except empty strings.

Any number is True, except 0.

Any list, tuple, set, and dictionary are True, except empty ones.

Example

The following will return True:

bool("abc")
bool(123)
bool(["apple", "cherry", "banana"])

Try it Yourself »

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Some Values are False

In fact, there are not many values that evaluate to False, except empty values, such as (), [], {}, "", the number 0, and the value None. And of course the value False evaluates to False.

Example

The following will return False:

bool(False)
bool(None)
bool(0)
bool("")
bool(())
bool([])
bool({})

Try it Yourself »