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while Loops

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  while Loops Elizabeth Weiss <cake240@gmail.com> - 2016-06-21 20:50 -0700
    Re: while Loops Wildman <best_lay@yahoo.com> - 2016-06-21 23:04 -0500
    Re: while Loops Rustom Mody <rustompmody@gmail.com> - 2016-06-21 21:04 -0700
    Re: while Loops Ben Finney <ben+python@benfinney.id.au> - 2016-06-22 14:02 +1000
    Re: while Loops Michael Torrie <torriem@gmail.com> - 2016-06-21 22:11 -0600
    Re: while Loops alister <alister.ware@ntlworld.com> - 2016-06-22 08:37 +0000
    Re: while Loops John Gordon <gordon@panix.com> - 2016-06-22 16:03 +0000

#110283 — while Loops

i=1
while i<=5:
   print(i)
   i=i+1

The result is:
1
2
3
4
5

Why is one of the results 5 since i=i+1? Should the maximum result be 4 since 4 +1=5? 

Thanks for your help!

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#110286

On Tue, 21 Jun 2016 20:50:24 -0700, Elizabeth Weiss wrote:

> i=1
> while i<=5:
>    print(i)
>    i=i+1
> 
> The result is:
> 1
> 2
> 3
> 4
> 5
> 
> Why is one of the results 5 since i=i+1? Should the maximum result be 4 since 4 +1=5? 
> 
> Thanks for your help!

The operator '<=' means less than or equal.  To get the results
you are expecting, you need to use '<' only.

i=1
while i<5:
    print(i)
    i=i+1

1
2
3
4

-- 
<Wildman> GNU/Linux user #557453
The cow died so I don't need your bull!

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#110287

On Wednesday, June 22, 2016 at 9:20:35 AM UTC+5:30, Elizabeth Weiss wrote:
> i=1
> while i<=5:
>    print(i)
>    i=i+1
> 
> The result is:
> 1
> 2
> 3
> 4
> 5
> 
> Why is one of the results 5 since i=i+1? Should the maximum result be 4 since 4 +1=5? 
> 

Not sure what your question is
But I guess you are being tripped up by a pervasive and confusing pun
which you are inadvertently(?) using in one line:

a> i = i+1
b> 4+1 = 5

a> is an assignment statement IN the programming language python
b> is a math statement ABOUT python

a> in math is meaningless  (unless i is ∞ or something)
b> in programming is a syntax error

If you feel you are confused thats good; most professional programmers are
more confused and dont know it.
The predecessor of python -- ABC -- wrote
i = i+1
as
PUT i+1 IN i

Unfortunately python followed the mainstream and confusified it to 
i=i+1

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#110288

Elizabeth Weiss <cake240@gmail.com> writes:

> Why is one of the results 5 since i=i+1?

What do you think ‘i = i + 1’ means? (Asking because your idea of what
that means may be affecting how you expect the loop to behave.)

> Should the maximum result be 4 since 4 +1=5?

Try “thinking like the computer”: perform the steps yourself, reading
each statement as though you are the computer. Keep a pad and pencil at
hand, and make notes on what changes as you go through. See what
you-as-computer actually emit onto the paper, and see whether that
matches what the Python session produces.

-- 
 \      “The difference between a moral man and a man of honor is that |
  `\   the latter regrets a discreditable act, even when it has worked |
_o__)                   and he has not been caught.” —Henry L. Mencken |
Ben Finney

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#110289

On 06/21/2016 09:50 PM, Elizabeth Weiss wrote:
> i=1
> while i<=5:
>    print(i)
>    i=i+1
> 
> The result is:
> 1
> 2
> 3
> 4
> 5
> 
> Why is one of the results 5 since i=i+1? Should the maximum result be 4 since 4 +1=5? 
> 
> Thanks for your help!

If you trace the execution through in your mind it should be come clear.
 While always checks the expression first before running the body of the
loop.  If, during the loop body, i was 4, it is then incremented to 5.
Now the top of the while loop checks the expression and since i is 5,
5<=5 is true (5 is less than or equal to 5), so the body runs now, and
prints out the value and then increments i by 6, making it 6.  Now at
the top of the while loop, 6 is clearly not less than or equal to 5, so
the loop terminates there.  Hope this helps.

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#110304

On Tue, 21 Jun 2016 20:50:24 -0700, Elizabeth Weiss wrote:

> i=1 while i<=5:
>    print(i)
>    i=i+1
> 
> The result is:
> 1
> 2
> 3
> 4
> 5
> 
> Why is one of the results 5 since i=i+1? Should the maximum result be 4
> since 4 +1=5?
> 
> Thanks for your help!

check you loop condition
while i lest than or equal to 5

so the loop will run for the case when i= 5 




-- 
Welcome to Utah.
If you think our liquor laws are funny, you should see our underwear!

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#110323

In <0cf9a94e-b84c-460d-b03d-edf6a941adc0@googlegroups.com> Elizabeth Weiss <cake240@gmail.com> writes:

> Why is one of the results 5 since i=i+1? Should the maximum result
> be 4 since 4 +1=5? 

"while i<=5" means "while i is less than or equal to 5".  So the loop
will keep going at 5, and only stop when i is 6.

-- 
John Gordon                   A is for Amy, who fell down the stairs
gordon@panix.com              B is for Basil, assaulted by bears
                                -- Edward Gorey, "The Gashlycrumb Tinies"

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