10/17/2011 cs lecture strings

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4/28/12

Do Now: 10 minutes

1. Type the following code into the Idle

text editor (File > New Window):

2. Run the program (Run > RunModule) for various inputs,

including inputs with numbers.

3. Write a one sentence description of what the code does.

print('Hello world!')print(‘Type your name and then press enter.’)myName = input()

print('It is good to meet you, ' + myName)



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Homework

• Handout: You may test your answersin Python if you wish

•

Useful Resource: Zelle textbookpages 39 – 43 (PDF pages 47-51)




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Strings

- Chunks of text

- Can store strings with variables, just likewe can store numbers

- Single or double quotes used to identifystrings




4/28/12

Strings

- Chunks of text

- Can store strings with variables, just likewe can store numbers

- Single or double quotes used to identifystrings

EXAMPLES:greeting = “hello”myName = ‘Matt’myAdvice = “You will not learn

programming in class. You will learnro rammin b writin code, messin u ,




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Characters

-Strings are made up of individual

characters think of a character as anysymbol you can type with a keyboard




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Characters

-Strings are made up of individual

characters think of a character as any

symbol you can type with a keyboard

Examples:LettersSpacesPunctuation




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print() function:

-A function that displays a string on thescreen.

-Ex: print(“hello world”)




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print() function:

-A function that displays a string on thescreen.

-Ex: print(“hello world”)

input() function:

-A function that waits for the user to enter astring and stores the string in a variable.

-Ex: inputString = input()




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len() function

-Identifies the number of characters in astring and stores it in a variable.

-Ex:

myName = “Matt”myNameLength = len(myName)




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len() function

-Identifies the number of characters in astring and stores it in a variable.

-Ex:

myName = “Matt”myNameLength = len(myName) 4




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String concatenation (+ operator)

-Puts strings together to form a singlestring

-Ex:

lastName = “Carlberg ”firstName = “Matthew ”fullName = firstName + lastName

Matthew Carlberg




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Substring

-retrieves specific characters from a string

-Ex:

lastName = “Carlberg”

firstLetter = lastName[0] CsecondLetter = lastName[1] a firstPartOfLastName = lastName[0:4]

Carl

secondPartOfLastName = lastName[4:8]berg




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bookstore = “Barnes & Noble” bookstoreLength = len(bookstore)

print(bookstore)

print(bookstoreLength)

Output?




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bookstore = “Barnes & Noble” bookstoreLength = len(bookstore)

print(bookstore)

print(bookStoreLength)

Barnes & Noble14

Output?




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bookstore = “Barnes\n&\nNoble” bookstoreLength = len(bookstore)

print(bookstore)


Output?




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bookstore = “Barnes\n&\nNoble” bookstoreLength = len(myString)

print(bookstore)


Barnes

&Noble14

Output?




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bookstore = “Barnes & Noble”test1 = bookstore[2:4]

test2 = bookstore[0]

test3 = bookstore[len(bookstore)-1]

crazy = test1 + test2 + “ ” + test3

print(crazy)

Output?




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bookstore = “Barnes & Noble”test1 = bookstore[2:4] rn

test2 = bookstore[0] B

test3 = bookstore[len(bookstore)-1] e

crazy = test1 + test2 + “ ” + test3

print(crazy)

Output?

rnB e

10/17/2011 cs lecture strings

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