Section 13.3 Compute with Words
The computer can also compute with words, or more accurately, with strings which are sequences of characters. We can create a string by typing characters between a pair of single ('Hi'), double ("Hi"), or triple quotes ('''Hi'''). We can “compute” with strings using some of the same basic arithmetic operators – they just mean something different here. Here we generate silly song lyrics by using + to combine (append) two strings and * to repeat strings.
Strings are different than numbers in that they are objects. Objects are complex entities in code that combine data (like the text that is part of a string) with behaviors - things the object can do. To access the behaviors of an object, we use dot-notation. In dot notation, we use a . (or dot) to describe which behavior of an object we want to make use of.
For example, the program below uses sentence.lower() to tell the string sentence that we want it to give us a copy of itself that has been changed to all lower-case letters. We then ask the new string, called better to make a copy of itself where just the first letter is capitalized.
Checkpoint 13.3.1.
What would the following code print?
first = "Hi"
next = "There"
print ((first + next) * 2)
Hi There
When you add strings together you copy the second string right after the first, without any added space
HiThere
Remember that * 2 repeats two copies of the same string
Hi There Hi There
Adding strings together and repeating them doesn’t add spaces between the strings
HiThereHiThere
Strings are added together without adding any space and they are repeated without adding a space
HiThere2
The * 2 repeats the string two times
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