I am new to Python was wondering what the purpose of "for loops" is? What do they do in a function/what output do they produce? When are they used?
(I've done some research on what a for loop is, but most sources are confusing/unclear so I decided to ask on here.)
Is the for loop function required in the following code dealing with filling in colors of a shape? I've seen some people use it when demonstrating examples of filling in color, but I'm not quite sure if it's required or what it does.
# Example code: I know, nothing is shown
# because I haven't told the function to draw anything, this is just an example.
t.pencolor("blue")
t.fillcolor("blue")
t.begin_fill()
for i in range(4):
# remove 'pass' and write some code here, for loop is not doing any thing.
pass
t.end_fill()
# I noticed that this code produced the same output as:
t.pencolor("blue")
t.fillcolor("blue")
t.begin_fill()
t.end_fill()
You use a for
loop whenever you need to do the same thing over and over (a) .
For example (using your "turtle" area of concern), say you wanted to draw a circle (or something approximating a circle). You could do this with something like:
pen down
for i in 1..360:
go forward 1 unit
turn right one degree
pen up
The alternative would be a rather long sequence of commands of the form:
got forward 1 unit
turn right one degree
got forward 1 unit
turn right one degree
got forward 1 unit
turn right one degree
: :
got forward 1 unit
turn right one degree
which nobody wants to read or debug:-)
(a) The way I teach beginners is to basically introduce them to the three main concepts of program flow:
for i in range(4):
t.forward(150)
t.right(90)
change range(1), range(2), range(3) then you will be able to see beauty of for loop.
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