Why do we use for app in app_data. What does the "app" stand for and who defined it in the code? Or is it a given a predefined meaning by Python

opened_file = open(‘AppleStore.csv’)
from csv import reader
read_file = reader(opened_file)
apps_data = list(read_file)

for app in apps_data[1:]:
price = float(app[4])

My question is, that when we used for row in apps_data, I got it cause I believe python understands what row is. But what does the “app” function do and is it a pre-existing function in Python or did we add it? In which case, where did we add it/

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Hi @learningpanda786,

Welcome to the Community!

Neither row in one example nor app in another one are functions. Instead, they are variables of that exact for-loop for each case. And when you write for row in apps:, Python doesn’t understand at all that row is a row. It only understands that it’s a variable of that for-loop that will have different values at each iteration. So instead of row or app, you can use whatever word as a name of that variable. A good practice, though, is to choose a word that fits the context and, hence, makes the code more readable. For example, for app in apps: is clear enough, meaning that we are iterating through each app in all apps available, etc.



just a follow up question - so in another word, we can use “row” or “app” in the For loop, as long as it fits the context?

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Hi @miah,

That’s correct! You can use any word for the iteration variable in the for-loop, and yes, the best strategy is to use a meaningful word that reflects the context.

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Thank you so much! Appreciate your help!

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