{"id":2599,"date":"2020-08-19T18:32:13","date_gmt":"2020-08-19T18:32:13","guid":{"rendered":"https:\/\/idiagress.com\/vinaaypatil\/?p=2599"},"modified":"2023-10-28T09:23:56","modified_gmt":"2023-10-28T09:23:56","slug":"1-5-loops-and-conditionality","status":"publish","type":"post","link":"https:\/\/idiagress.com\/vinaaypatil\/2020\/08\/19\/1-5-loops-and-conditionality\/","title":{"rendered":"1.5 Loops and Conditionality"},"content":{"rendered":"\n

Let’s jump directly into some programming. Using concepts learned so far, let\u2019s create a program to calculate the average height of three students (three_average.py)<\/p>\n\n\n\n

three_average.py<\/b><\/span><\/td><\/tr>
# program to calculate average height of three students<\/i>
<\/span>  <\/span>
<\/span># get input of height<\/i>
<\/span>_a1= <\/span>float<\/span>(<\/span>input<\/span>(<\/span>“Enter height of first student (cm): “<\/span>))
_a2= <\/span>float<\/span>(<\/span>input<\/span>(<\/span>“Enter height of second student (cm): “<\/span>))
_a3= <\/span>float<\/span>(<\/span>input<\/span>(<\/span>“Enter height of third student (cm): “<\/span>))
   <\/span>
<\/span># use the formula for average = Sum of values\/ total number of values<\/i>
<\/span>_avg=(_a1+_a2+_a3)\/(<\/span>3<\/span>)
  <\/span>
<\/span># print the output<\/i>
<\/span>print<\/span>(<\/span>“The average height is: “<\/span>, _avg)<\/span><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

At the output we get,<\/p>\n\n\n\n

<\/div>\n\n\n
\n
\"\"<\/a><\/figure>\n<\/div>\n\n\n
<\/div>\n\n\n\n

Creating a More Versatile Program<\/strong><\/p>\n\n\n\n

While the initial program successfully calculates the average height of three students, it falls short in scenarios involving a larger number of students. Consider a situation with ten students\u2014writing ten input commands for each student’s height isn’t practical. Furthermore, creating a new program for each change in the number of students is inefficient.<\/p>\n\n\n\n

To address these issues, we need a single program capable of accommodating various scenarios. The key to achieving this flexibility lies in the concept of loops.<\/p>\n\n\n\n

Introducing Loops<\/strong><\/p>\n\n\n\n

Loops are a fundamental programming structure that enables us to repeat a sequence of instructions multiple times. In essence, they help us automate tasks that need to be executed a certain number of times.<\/p>\n\n\n\n

One common and powerful type of loop is the ‘for’ loop. Below is a typical syntax for using a ‘for’ loop:<\/p>\n\n\n\n

<\/div>\n\n\n\n

for<\/span> _num <\/span>in<\/span> range<\/span>(<\/span>0<\/span>, <\/span>5<\/span>, <\/span>1<\/span>):
<\/span>    <\/span><\/span>print<\/span>(<\/span>\u201chello”<\/span>)<\/span><\/p>\n\n\n\n

 <\/span>If executed, we will get the output below<\/p>\n\n\n\n

<\/div>\n\n\n
\n
\"\"<\/a><\/figure>\n<\/div>\n\n\n
<\/div>\n\n\n\n

Let’s delve into the ‘for<\/strong>‘ loop, a fundamental programming construct used for repeating a sequence of instructions. To illustrate this concept, let’s break down the components of a ‘for’ loop used in our example:<\/p>\n\n\n\n

for _num in range(0, 5, 1):\n    # Code inside the loop<\/code><\/pre>\n\n\n\n
    \n
  1. ‘_num’ – The Variable<\/strong>: In Python, you can use any variable as the loop control variable. Here, we’ve used ‘_num’ as an example, but you can choose a variable name that suits your needs.<\/li>\n\n\n\n
  2. The range()<\/code> Function<\/strong>: The range(0, 5, 1)<\/code> defines the behavior of the loop.\n