🔁 Coding · Ages 9 to 15 · 1:06
Python loops: what a for loop does
Why write the same line five times when a loop can repeat it? See for i in range(5) run step by step, watch i count 0 to 4, then print the square numbers and change 5 to 100.
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In this video
- 0:00 Say hello five times
- 0:13 A for loop
- 0:41 Use the counter
Transcript
0:01 Imagine saying hello to five friends. You could write the same line five times.
0:07 Or you could ask the computer to repeat it for you. That's a loop.
0:13 Here it is. For i in range of five, print hello.
0:21 Range of five counts zero, one, two, three, four. Five numbers.
0:28 Each time round, i takes the next number, and the indented line runs once.
0:35 Round and round it goes. Five hellos, from just two lines.
0:41 Now let's use i itself. Print i times i.
0:46 Zero, one, four, nine, sixteen. The square numbers, made by the loop.
0:55 Change five to a hundred, and you get a hundred square numbers, just like that.
1:01 A loop repeats your code, so you don't have to.
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