I’m new to while loops, and I don’t quite get what’s going on in this code from my book: current_number = 1 while current_number More on discuss.python.org

It has nothing to do with the loop or it's conditional. Instead, it is copying the variable head to the variable current. Current is then converted to a boolean and checked for it's 'truthiness' as Mariusz Jamro's answer below explains. ... The while current: syntax literally means while bool(current) == True:. The value will be converted to bool first and than compared to True. In python ... More on stackoverflow.com

Why would somebody use a loop construct when there is goto? Why would somebody use a high-level language when there is assembly language? Why would somebody name their variables when they can just use the memory addresses?

Answer: Because writing code that intuitively "looks like" the thing it is intended to do, both a) makes writing programs much less work, b) dramatically reduces the number of bugs, and c) greatly decreases the difficulty of reading, understanding, and maintaining the code later.

We use for loops when we want to loop over a range, or loop over the elements of a set. This is a fixed operation over a known amount of steps. Essentially, we are saying something along the lines of "for each employee, calculate the salary and submit a payment", so we call it "for" to highlight this relationship. In the case of Python, for loops also provide a special efficient syntax for looping over the elements of a set, so it's less work to type the thing in too. Some other languages call that variant of the for statement "foreach".

We use while loops when we want to continue repeating an operation while a condition continues to hold. For example, we continue looping as long as we encounter no errors, or as long as we receive more data from a network connection. These are not fixed ranges, but take place while a condition holds, so we call it "while".

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Consider how the terms are used in common language: FOR For each day in July, I will practice writing loops. For every student in the class, provide a lunchtime meal. For each letter in the alphabet, write down a word beginning with that letter. For numbers in the range 1 to 10, calculate the square root. Notice that for each case, we iterate through multiple things (days in the month / students in the class / letters in the alphabet / numbers in a range). WHILE While there is still daylight, we can play football. While the music is playing, we will dance. While I am waiting, I will read a book. While my set of Pokémon cards is incomplete, I will keep collecting them. Notice that in each case, something is done for as long as a condition (a "predicate") is satisfied (is "True"). In these examples, the predicates are: "There is daylight?", "The music is playing?", "I am waiting?", "The set is incomplete?". As soon as the answer is "False", the loop stops. More on reddit.com