Module: (Python) Loops. Loop with counter - for


Problem

2/15

Features of the for loop

Theory Click to read/hide

Features of the for

loop How to change the step in the sequence of values ​​and not start from scratch? The  range() function, by default, builds a sequence in which each next number is 1 greater than the previous one. You can use the range function in another entry.

The general form of the function entry is as follows: 
range([start], stop[, step])
  • start: start number of the sequence.
  • stop: generates numbers up to but not including the given number.
  • step: the difference between each number in the sequence (step)

You have to remember!
  • All parameters must be integers:
  • Each of the parameters can be either positive or negative.
  • range() (and Python in general) is based on index 0. This means that the index list starts at 0, not 1.  The last integer generated by the function  range() depends on stop but will not include it. For example, range(0, 5) generates the integers 0, 1, 2, 3, 4, not including 5.


Example 1
for i in range (10, 0, -1):
    print(i*i)
The program displays the squares of natural numbers from 10 to 1 in descending order
  • 10: The first number in the sequence.
  • 0: end number of the sequence (not including this number).
  • -1: step


Example 2
for i in range (0, 101, 5):
    print(i)
The program displays all numbers from 0 to 100 in increments of 5
  • 0: The first number in the sequence.
  • 101: end number of the sequence (not including this number).
  • 5: step

Problem

The above program displays numbers from 1 to 10 in a column. You can verify this by running it.
By changing the value of the loop variable from the value equal to 1 to the value equal to 10, in increments of +1, the value of the i variable is displayed on the screen in the body of the loop.
To pass the test, you need to make sure that the program displays all the numbers from 20 to 30 in the same column.

Change the title of the loop so that the program displays numbers from 20 to 30.

time 1000 ms
memory 256 Mb
Rules for program design and list of errors in automatic problem checking

Teacher commentary

Insert the missing code snippets
Python
1
2 
    print (i)

     

Program check result

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