1.4 String basics

Learning objectives

By the end of this section you should be able to

Use the built-in len function to get a string's length.
Concatenate string literals and variables using the + operator.

Quote marks

A string is a sequence of characters enclosed by matching single (') or double (") quotes. Ex: "Happy birthday!" and '21' are both strings.

To include a single quote (') in a string, enclose the string with matching double quotes ("). Ex: "Won't this work?" To include a double quote ("), enclose the string with matching single quotes ('). Ex: 'They said "Try it!", so I did'.

**Table 1.3** Rules for strings.
Valid string	Invalid string
`"17" or '17'`	`17`
`"seventeen" or 'seventeen'`	`seventeen`
`"Where?" or 'Where?'`	`"Where?'`
`"I hope you aren't sad."`	`'I hope you aren't sad.'`
`'The teacher said "Correct!" '`	`"The teacher said "Correct!" "`

len function

A common operation on a string object is to get the string length, or the number of characters in the string. The len function, when called on a string value, returns the string length.

Concatenation

Concatenation is an operation that combines two or more strings sequentially with the concatenation operator (+). Ex: "A" + "part" produces the string "Apart".

Try It

Name length

Write a program that asks the user to input their first and last name separately. Use the following prompts (example input in bold):


  What is your first name? Alan
  What is your last name? Turing

The program should then output the length of each name. Based on the example input above, the output would be:


  Your first name is 4 letters long
  Your last name is 6 letters long

Try It

Punctuation

Write a Python computer program that:

Assigns the string "Freda" to a variable, name.
Assigns the string "happy" to a variable, feel.
Prints the string "Hi Freda!" with a single print function using the variable name.
Prints the string "I'm glad you feel happy." with a single print function using the variable feel.

# Type your code after this comment

Adapted from Introduction to Python Programming by OpenStax (openstax.org), licensed under CC BY-NC-SA 4.0. Changes were made. License: CC-BY-NC-SA-4.0.