^{(This post is best viewed on Steempeak.com)}
i once again !! 👋
Hope you liked the previous article Let's Learn Python 🐍, and it helped give you a mild flavor of what Python is.

In this article we'll go ahead and try to learn loops in Python.

^{(This article will be a continuation of the last one, so if you have not read the last one, I strongly urge you to read it before you start this one.)
(The worst piece of code I could find on Pixabay! Never forget to properly space, indent and comment your code. It should be legible and readable!)}

Starting where we left...

Last time, I left you with a problem: > **Problem:** Can you write Python code to print numbers from 1 - 1000? (Without explicitly stating all the numbers.) > Let's try solving it right away, I'll directly give you the code to ponder upon, later we'll see how it works when we formally describe *loops* and their different types.

Let's see if the following piece of code can do our work:

i=1
while(i<=1000):
    print(i)
    i+=1

...and there, we got the desired output with just a 4-liner code!

Notice: The i+=1 in the code. This statement contains the compound augmented operator += we discussed in the previous article. i=1 gives i the initial value of 1. Rest is all logical.

NOTE: i is often referred to as the sentry variable or more generally a counter.

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Okay! Before we move into loops, we'll try to learn a few interesting things:

• Using range:
  Just look at this piece of code for a while, and you should be able to make out what it's doing...

print(*range(0, 10, 1))
print(*range(0, 10, 3))

print(range(0, 10, 1))
print(*range(1, 11, 1))

 >**NOTE:** >1. The first line in the code simply prints no.s. from `0 to 10 with an interval of 1 unit`. >2. The second line prints no.s. from `0 to 10 with an interval of 3`. >3. The third prints the `range(0, 10) with interval of 1. This defaults to range(0, 10)`. >3. The fourth prints `range(1, 11) with interval of 1 which also defaults to range(1,11)`, but is printed explicitly due to *. >>**NOTE:** * is used to print the ranges explicitly. >> Now, you may be wondering why we used `for` Loop in the question I gave you! 😃 Well, yes frankly speaking even I am wondering! Haha! Never mind, it is true that we can print the numbers from 1 to 1000 using `range()` as well:
```python print(*range(1, 1001)) ```  - ****

  3.2. Loops in Python

Python has 2 basic loops: - **For Loop** --> `for` The syntax for this loop is: ```python for in : <...and this> ``` - **While Loop** --> `while` The syntax for *while loop* looks like this: ```python while : ```
^{(While Loop Flowchart | **Source:** Wikimedia Commons)} Okay, so now I guess though the `while` Loop is a bit self-explanatory, but the `for` Loop may need a bit of examples to understand.
So, let's see a few examples of both of these: - `for`Loop: >**Example - 1)** Let's try to print the numbers from 1-1000 using `for` Loop. >```python >for x in range(1, 1001, 1): > print(x) >``` > >...that was easy! wasn't it?...we got all the numbers printed one below the other. Now, let's try a more useful and challenging program... > >**Example - 2)** Let's write a python program which allows the user to check whether we have a particular fruit in our basket containing apple, mango, guava, avocado, coconut, pineapple...or not. >```python >basket=("apple", "mango", "guava", "avocado", "coconut", "pineapple") >fruit=input("Please pick a fruit to see if it is in your basket. Type it's name to pick.") >for x in basket: > if(x==fruit): > print("CONGRATULATIONS! We have ", fruit, "in our basket") >``` > >>**NOTE:** >>1. In the above example we have defined the variable `basket` and have stored a set of strings in it. So, `basket` is technically speaking a ***tuple*** (as of now, you can consider it as a list of objects). >>2. `input()` is a function used to take input from the user. In our case, `input()` takes the name of the fruit from the user (anything specified within this function is printed as a text to direct the user to input the desired things. It acts just like `print()`), and assigns the string entered by the user to the variable `fruit`. >>3. The other thing that is important to notice is the fact that in `if(x==fruit)`, we are using operator `==` instead of `=`. Reason being that using the latter would assign `x` the value contained in `fruit`, while `==` only checks whether the two are equal. > - **`while` Loop:** >Okay, we have already seen a problem which we solved using `while`. Let's try one more: >**Example - 1)** Let's write a program to print the multiplication table of 2. >```python >i=1 >while(i<=10): > print("2 x ", i, "=", 2*i) > i+=1 >``` > >Well!! That was simple wasn't it? If you are confused, try to read the code line-by-line, and logically think what each line is doing, and how the computer will understand the code. >

Okay, that was simple! But here is an important advice and a note of caution:

NOTE:

Indentation is very important in Python. If you wrongly indent the code, then the interpreter will understand it differently.

For example:

if(x==5):
	<do task-A>
	<do task-B>

..means, if x is equal to 5, do tasks A and B.
Whereas,

if(x==5):
	<do task-A>
<do task-B>

...would mean: if x is equal to 5, do task A. After if block has been implemented, do B (irrespective of the value of x).

Okay, now we somewhat have an idea of basic loops in Python. These loops can be put one-inside the other i.e. they can be nested.

I introduced the operator ==. So, now that we already know one, let's have a look at the others as well:

• Logical Operators in Python:
  
• Boolean Operators in Python:
  

I hope that understanding these operators shouldn't be a difficult task, you can also try using them in if, for and while loops.

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That's all for today, hope that you are enjoying these short lessons.

NOTE: Unless otherwise stated, all pictures are mine, and have been taken from my own notes, or are my VS Code screenshots.

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With this I'll take your leave.

Thanks for sparing your time!
Keep slithering !!
Best,
Aakash