Good day nairalanders, I started learning Python some weeks ago and I'm kinda having problems in understanding 'loop'.

Like what is it used for
What situation do we need to use it

Pls can someone help me out, it's really drawing me back

manuel4real:
Good day nairalanders, I started learning Python some weeks ago and I'm kinda having problems in understanding 'loop'.

Like what is it used for
What situation do we need to use it

Pls can someone help me out, it's really drawing me back

Loops are used to repeat a particular set of instructions more than once.

Loops are used to repeat or iterate over a set of instructions as long as the condition holds
Take the while loop for example
(1) x = 1
(2) while i <=5: // this is the condition
(3) print(i)
(4) x = x + 1
So first the value of x = 1, then in line 2 it checks if x which is 1 is less than or equal to 5, in line 3 it then prints 1, on the 4th line x = x + 1, is the same as x = 1 + 1, which means x is now 2, it goes back to the condition to check if 2 is less than or equal to 5 , then it prints 2, it increments 2 to 3, it repeats this until i meets the condition (i<=5)
The statements inside it are repeatedly executed, as long as the condition holds.

Loops can be used in game development , you need a game loop that repeats the drawing of board, movement of items, input etc.

Hope it helps

SegFault:

Loops are used to repeat a particular set of instructions more than once.

thank you very much sir.

Loop is like running around circles until a given condition is met.

Take for instance i asked you to buy me fish, you went and bought yam, i asked you to return the yam and buy me fish, you returned it and bought beans, I asked you to return the beans and buy me fish , you returned the beans and bought rice.
Not until you buy me the fish I sent you. You will continue to repeat the errand that I sent you. Though I can say if you run the errand for certain amonunt of times like 2,3, or any amount of time without buying the fish I sent you. I can ask you to stop. That is what you call break in loops.

To gain more understanding on loops read the book. 'Automate the boring stuff with python'. Take your time and read flow control on chapter 2.

manuel4real:
Good day nairalanders, I started learning Python some weeks ago and I'm kinda having problems in understanding 'loop'.

Like what is it used for
What situation do we need to use it

Pls can someone help me out, it's really drawing me back

for example if you need to print 1 - 1000. Can you help with any method of doing this without using a loop?

If you were asked to print a calendar, is there any way to do it without a loop.

If I give an array of numbers with around 250 element and I told you to multiply each by 5. Can you suggest any other way to accomplish this task without loop.

Loop is the heart of computing, computer are better than us in speed and repetition and accuracy.
This three hallmark is the essence why anyone would learn how to program and use the advantage of a computer.

Many apps and program you use today make extensive use of repetition and shockingly your OS(windows/Linux) is a one big Unending loop that run different statement on each iteration.

So also a loop is what keeps a system on and running.
A loop is what keeps a server running.
If you can solve a task with a loop then you understand computing.

1-100

I want to read the numbers in that range. I can follow 3 ways: while, do while and for loops. this simply mean I want to read from 1 to 100, reading this involves iteration i.e repeating. so, you are going start from 1 which is the starting point to 100 which is the target point. I am going to use Java as I'm a Java dev. let's go.

for(int i=1; i<=100; i++){
      System.out.println("Number : " +i);
}

The above code will print: Number : 1 to Number : 100

that is for for loop

int i =1;
          while (i<=100){
          System.out.println("Number : " +i );
         i++;
     }

this is while loop

int i =1;
          do{
           System.out.println("Number : " + i);
            i++;
         }while(i<=100);

this for do while loop.


For the above code snippets you gonna get the same result that is, Number 1 - Number 100

There is another loop called foreach or enhancedfor loop

for(int  var : refVar){
   System.out.println(var);
  }

that's the syntax.

Coder2Client:
1-100

I want to read the numbers in that range. I can follow 3 ways: while, do while and for loops. this simply mean I want to read from 1 to 100, reading this involves iteration i.e repeating. so, you are going start from 1 which is the starting point to 100 which is the target point. I am going to use Java as I'm a Java dev. let's go.

for(int i=1; i<=100; i++){
      System.out.println("Number : " +i);
}

The above code will print: Number : 1 to Number : 100

that is for for loop

int i =1;
          while (i<=100){
          System.out.println("Number : " +i );
         i++;
     }

this is while loop

int i =1;
          do{
           System.out.println("Number : " + i);
            i++;
         }while(i<=100);

this for do while loop.


For the above code snippets you gonna get the same result that is, Number 1 - Number 100

There is another loop called foreach or enhancedfor loop

for(int  var : refVar){
   System.out.println(var);
  }

that's the syntax.

Op wasn’t asking for syntax or implementation but justification for a programmer to understand a loop.

But anyway I consider your approach a pragmatic one though

manuel4real:
Good day nairalanders, I started learning Python some weeks ago and I'm kinda having problems in understanding 'loop'.

Like what is it used for
What situation do we need to use it

Pls can someone help me out, it's really drawing me back

Imagine you are trying to fill a bucket with a bowl, taking water from a big drum .
You would keep scooping from the drum with the bowl until the bucket is full.
So a loop is a repetitive action until the aim is achieved, once the aim is achieved, the action (in this case, filling the bucket) is terminated.

This is a layman simplified real-world explanation .

In coding, an example where it can be used is :

For example you have a system where you want to sum up all the scores of all the courses a student does :
You can loop through all the scores and keep adding it up until its done .

Although there are better ways of adding this up instead of using a loop, but that's one way you can use it.

Donald3d:


Imagine you are trying to fill a bucket with a bowl, taking water from a big drum .
You would keep scooping from the drum with the bowl until the bucket is full.
So a loop is a repetitive action until the aim is achieved, once the aim is achieved, the action (in this case, filling the bucket) is terminated.

This is a layman simplified real-world explanation .

In coding, an example where it can be used is :

For example you have a system where you want to sum up all the scores of all the courses a student does :
You can loop through all the scores and keep adding it up until its done .

Although there are better ways of adding this up instead of using a loop, but that's one way you can use it.

I don’t think there is a better way other than loop. Loop is the backbone of working with collections. It can be decorated to what we call iteration and the rest but the inner structure remains a loop.

manuel4real:
Good day nairalanders, I started learning Python some weeks ago and I'm kinda having problems in understanding 'loop'.

Like what is it used for
What situation do we need to use it

Pls can someone help me out, it's really drawing me back

loops are use for truncating iterable data structure. a perfect example is the for loop. It allows you to list all elements in an iterable data structure.
to illustrate this for you, A list is a perfect example of python data structure.
list=[a,b,c,d]
Now with the for loop (an example of loop) we can printout all the element(data) in that data structure (list) by doing the following:
for i in list:
print(i)
this print out all the elements inside list like this:
a
b
c
d

stanliwise:
I don’t think there is a better way other than loop. Loop is the backbone of working with collections. It can be decorated to what we call iteration and the rest but the inner structure remains a loop.

I know loops are great but as one goes on in programming, you would have to find quicker ways to solve problems .

Something as simple as sum() would sum up the scores, depending on the data type or origin.

Donald3d:


I know loops are great but as one goes on in programming, you would have to find quicker ways to solve problems .

Something as simple as sum() would sum up the scores, depending on the data type or origin.

Maybe you would check the internal structure of sum();

Now matter how advance you’re in programming, no one ever evade loop

As a beginner in programming, to understand how loop works. You need to understand your iniquity in algebra.

Loop use more of logical operation to make decisions.
I will advice you go back to your basic algebra and study inequities.

Tim1212:
As a beginner in programming, to understand how loop works. You need to understand your iniquity in algebra.

Loop use more of logical operation to make decisions.
I will advice you go back to your basic algebra and study inequities.

please stay away from this advise

stanliwise:

Maybe you would check the internal structure of sum();

Now matter how advance you’re in programming, no one ever evade loop

You are being unnecessarily analytical, in the real world nobody cares about the internal structure of things, your result is what matters.
Why re-inventing the "internal structure", when it has already been done for you.

If you look under the hood, everything has an internal structure, so should we start re-inventing all of them ?

A good programmer keeps things as simple as possible, as long as the result is the same and it doesn't affect performance.

Besides, I never said loops are bad, I use them practically everyday. My point is in some cases there are faster ways to do things than using loops directly.

Donald3d:


You are being unnecessarily analytical, in the real world nobody cares about the internal structure of things, your result is what matters.
Why re-inventing the "internal structure", when it has already been done for you.

If you look under the hood, everything has an internal structure, so should we start re-inventing all of them ?

A good programmer keeps things as simple as possible, as long as the result is the same and it doesn't affect performance.

Besides, I never said loops are bad, I use them practically everyday. My point is in some cases there are faster ways to do things than using loops directly.

Since you mentioned the word “directly” then it is fine.
Loop is the heart of programming language

stanliwise:
please stay away from this advise

-)

stanliwise:

Maybe you would check the internal structure of sum();

Now matter how advance you’re in programming, no one ever evade loop

You would have to at sometime especially when you understand computer architecture, for example loops are tasking to the CPU cache and CPU pipelining though CPU caches are now larger than life 64kb is a lot trust me. But if you get to work on embedded systems you might face this problem.

Thank you all, I now understand it perfectly

SegFault:

You would have to at sometime especially when you understand computer architecture, for example loops are tasking to the CPU cache and CPU pipelining though CPU caches are now larger than life 64kb is a lot trust me. But if you get to work on embedded systems you might face this problem.

without loop there is no need for a computer. Simple and short.

The three hallmark for a computer till day is speed, accuracy and repetition.
Aside this human excel in all.

stanliwise:
without loop there is no need for a computer. Simple and short.

The three hallmark for a computer till day is speed, accuracy and repetition.
Aside this human excel in all.

I am not saying that loops aren't useful I am saying that you can't get the performance you need all the time using loops. Sometimes you need to cut down on the use of loops.

SegFault:

I am not saying that loops aren't useful I am saying that you can't get the performance you need all the time using loops. Sometimes you need to cut down on the use of loops.

suggest an alternative for loop please?
If for example I need to write one to one thousand.
I am expecting you to say recursion but you wouldn’t say that. would you?

stanliwise:
suggest an alternative for loop please?
If for example I need to write one to one thousand.
I am expecting you to say recursion but you wouldn’t say that. would you?

Please read and understand my mention once again. I simply said sometimes you'd have to use some other method other than loops. Besides recursion is worse than loops, it consumes stack space.

SegFault:

Please read and understand my mention once again. I simply said sometimes you'd have to use some other method other than loops. Besides recursion is worse than loops, it consumes stack space.

And what I am simply telling you is that there is nothing that replaces loop. Loop is among the bedrock of computer. I mean nothing, like simply nothing.

stanliwise:
And what I am simply telling you is that there is nothing that replaces loop. Loop is among the bedrock of computer. I mean nothing, like simply nothing.

Chai you still don't get what I am saying fashi. Funny thing about computers is that there is no provision for a loop instruction except for Intel processors (which no one uses). Back then when caches were small people had to cut down on the way they use loops (read Art of Assembly by Randall Hyde if you think this is a lie) when there was an alternative they chose it over loops. Now it is even better because CPUs are smart enough to know how many times a piece of code is run. If you ever do embedded system programming and you meet a microcontroller with a small cache you will understand finally what I mean.

SegFault:

Chai you still don't get what I am saying fashi. Funny thing about computers is that there is no provision for a loop instruction except for Intel processors (which no one uses). Back then when caches were small people had to cut down on the way they use loops (read Art of Assembly by Randall Hyde if you think this is a lie) when there was an alternative they chose it over loops. Now it is even better because CPUs are smart enough to know how many times a piece of code is run. If you ever do embedded system programming and you meet a microcontroller with a small cache you will understand finally what I mean.

ok we would leave it at this places but for your info I do Embedded system programming. Majorly Arduino. Using C++

stanliwise:
ok we would leave it at this places but for your info I do Embedded system programming. Majorly Arduino. Using C++

Okay good. You a hobbyist or a professional.

see no mind all these people bombarding your thread with syntax.
Basically 'loop' is used to repeat a particular set of instructions.
For instance, if you want to design a program that asks for a user's passcode to gain access, The 'loop' can be used to repeatedly ask the user to enter the correct passcode until the user gets the passcode right. So basically, if the user enters a wrong passcode, the program will ask for passcode again and if the user still enters a wrong passcode, the program will keep asking for passcode until user gets it right.

Danke!

manuel4real:
Good day nairalanders, I started learning Python some weeks ago and I'm kinda having problems in understanding 'loop'.

Like what is it used for
What situation do we need to use it

Pls can someone help me out, it's really drawing me back

SegFault:

Okay good. You a hobbyist or a professional.

My course of study is computing science actually. Professionally I am a web dev going to app dev but do embedded system as a hobby now sha

stanliwise:
My course of study is computing science actually. Professionally I am a web dev going to app dev but do embedded system as a hobby now sha

Hmm good. Downloaded an embedded systems book sometime ago when I don't even have one man I really need to get an arduino or raspberry pi to experiment on.

SegFault:

Hmm good. Downloaded an embedded systems book sometime ago when I don't even have one man I really need to get an arduino or raspberry pi to experiment on.

its cheap and easy to get