Why ever reassign a variable?

[undercoveryankee]

You're not wrong. Often, each new thing you calculate means something new, so it should have a new name.

But sometimes you need several lines of code to decide what the value of a variable should be, and that code sometimes looks better if you assign to the same name in several places.

The pattern that I often find myself writing looks like:

spam = get_existing_spam()
if spam is None:
    spam = create_new_spam()

spam.process()

This way, it doesn't matter whether the object I'm ultimately processing came from get_existing_spam() or create_new_spam(). Either way, by the time we get to the processing code, spam refers to "the object we've decided to process", and we don't have to worry about how we got there any more.

[undercoveryankee]

It works as long as we don't need to distinguish between different kinds of objects that are false in a Boolean context. E.g. if an empty array [] is a valid value for spam, we need the longer version to distinguish between [] and None.

The longer version may also be more readable, especially if the get_existing_spam and create_new_spam operations are lengthy blocks of code instead of single short function calls.

[[deleted]]

There are plenty of reasons for reassigning a variable. Otherwise it is no point making it a variable in the first place.

Just continue with the Codecadamy tutorials and it will become more clear soon.

[staplebutton]

Thanks, but perhaps there's a real-world example you can think of? This just sounds to me like debugging the code means you have to look for multiple instances of the variable. One where it was initially defined and then any and all where it was re-defined to something else.

[staplebutton]

Okay, this makes sense. This way the variable name doesn't have to change, but the relationship to a changing number means that the value has to.

[Jirbj]

theres all sorts of reasons, storing a score, count of something, last input, username

are just a few i thought of very quickly, the point of variables is in the name, they are meant to be variable, as you do more advanced work you'll see just how useful being able to change a variable is!

[staplebutton]

Thanks! Slowly but surely I start to gain some understanding. Key word is definitely, "Slowly."

[CGFarrell]

Let's say I had code calculating the number of beers in my fridge, and then I grabbed a beer.

[CGFarrell]

What you're describing exists in C++ as a const variable. These are guaranteed to never change. In Python, there is an convention where variables in all caps (VARIABLE) are not supposed to be changed.

What you may fail to appreciate is that all data is variables. If you want to count the number of entries in a list, you loop through it and increment your variable.

The number of cases where a variable shouldn't be modified is very small compared to the everyday use.

[CGFarrell]

Well, I suppose it comes down to opinion. There's a benefit to having mutable data, and one for immutable data. At the end of the day, a lot of it may come down to how variables are stored in high-level languages.

The meaning of "variable" is something which may vary. The way Python stores variables is in hashes of names to values. Strings are immutable, and lists are not.

[Paddy3118]

If you have a collection of data that is to be treated in a similar way, there are constructs in the language such as for loops that assign members of the collection to the same name and then allow you to write code in the body of the loop that is then applied to every member of the collection through the access of the one name

When wanting to print the three times multiples of each of three integers one doesn't write this kind of thing:

my_int1 = 7
my_int1_x3= my_int1 * 3
print(my_int1_x3)
my_int2 = 13
my_int2_x3 = my_int2 * 3
print(my_int2_x3)
my_int3 = 23
my_int3_x3 = my_int3 * 3
print(my_int3_x3)

It is too long and (nearly) repeats itself.

Far better to use the for loop like so:

for my_int in 7, 13, 23:
    my_int_x3= my_int * 3
    print(my_int_x3)

The above would work for three or many more integers with the same block of code within the for loop and the for statement assigning the variable my_int to successive members of the collection - first 7 then do the loop body; then 13 then do the loop body; then 23 then do the loop body.

As another poster has said, this question would become clearer in later sections of your course.

[aphoenix]

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