Conditionals and Control Flow
Learn how to use conditionals and control flow to create programs that generate different outcomes.
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Just like in real life, sometimes we'd like our code to be able to make decisions. The Python programs we've written so far have had one-track minds: they can add two numbers or [...] something,...
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Let's start with the simplest aspect of control flow: comparators. There are six: Equal to ( [...] ) [...] Not equal to ( [...] ) [...] Less than ( [...] ) [...] **Less...
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Excellent! It looks like you're comfortable with basic expressions and comparators. But what about extreme expressions and comparators?
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Comparisons result in either True or False, which are booleans as we learned before in this exercise . [...] Let's switch it up: we'll give the boolean, and you'll write the expression, just l...
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Boolean operators compare statements and result in boolean values. There are three boolean operators: 1. [...] , which checks if both the statements are [...] ; 2. [...] , which checks if a...
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The boolean operator [...] returns [...] when the expressions on both sides of [...] are true. For instance: [...] is [...] ; [...] is [...] .
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The boolean operator [...] returns [...] when at least one expression on either side of [...] is true. For example: [...] is [...] ; [...] is [...] .
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The boolean operator [...] returns [...] for false statements and [...] for true statements. For example: * [...] will evaluate to [...] , while [...] will return [...] .
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Boolean operators aren't just evaluated from left to right. Just like with arithmetic operators, there's an order of operations for boolean operators: 1. [...] is evaluated first; 2. [...] is ...
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Great work! We're almost done with boolean operators. [...]
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[...] is a conditional statement that executes some specified code after checking if its expression is [...] . Here's an example of [...] statement syntax: [...] In this example, [...] ...
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Let's get some practice with [...] statements. Remember, the syntax looks like this: [...] Looking at the example above, in the event that [...] returns [...] , then the indented block of ...
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The [...] statement complements the [...] statement. An [...] / [...] pair says: "If this expression is true, run this indented code block; otherwise, run this code after the else statement."...
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[...] is short for "else if." It means exactly what it sounds like: "otherwise, if the following expression is true, do this!" [...] In the example above, the [...] statement is only checke...
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Really great work! Here's what you've learned in this unit: Comparators [...] Boolean operators [...] Conditional statements [...] Let's get to the grand finale.
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Now let's take what we've learned so far and write a Pig Latin translator. Pig Latin is a language game, where you move the first letter of the word to the end and add "ay." So "Python" becomes "y...
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Let's warm up by printing a welcome message for our translator users.
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Next, we need to ask the user for input. [...] In the above example, [...] accepts a string, prints it, and then waits for the user to type something and press Enter (or Return). In the inte...
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Next we need to ensure that the user actually typed something. [...] We can check that the user's string actually has characters!
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Now we know we have a non-empty string. Let's be even more thorough and check that our string only contains letters. Consider the following code: [...] In the first line, we create a strin...
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When you finish one part of your program, it's important to test it multiple times, using a variety of inputs.
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Now we can get ready to start translating to Pig Latin! Let's review the rules for translation: You move the first letter of the word to the end and then append the suffix 'ay'. Example: pytho...
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Let's simplify things by making the letters in our word lowercase. [...] The [...] function does not modify the string itself, it simply returns a lowercase-version. In the example above, we ...
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Now that we have the first letter stored, we need to add both the letter and the string stored in [...] to the end of the original string. Remember how to concatenate (i.e. add) strings together...
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Well done! However, now we have the first letter showing up both at the beginning and near the end. [...] 1. First we create a variable [...] and give it the string [...] 2. Next we access ...
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Yay! You should have a fully functioning Pig Latin translator. Test your code thorougly to be sure everything is working smoothly. You'll also want to take out any [...] statements you were usin...
What you'll create
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How you'll master it
Stress-test your knowledge with quizzes that help commit syntax to memory
Conditionals and Control Flow
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