math.sqrt() in new 3.0 version : solution in input()
David
David
Sat Dec 27 03:34:45 CET 2008
On Fri, 26 Dec 2008 15:52:24 -0600, David Lemper wrote:
>At the command line this function works correctly
> >>> import math
> n = input("enter a number > ")
> s = math.sqrt(n)
> An entry of 9 or 9.0 will yield 3.0
>
>Yet the same code in a script gives an error message
> Script1
> import math
> n = input("enter a number > ")
> s = math.sqrt(n)
>
> Traceback (most recent call last) :
> File "<stdin>", line 1, in <module>
> File "script1.py" line 3 in <module>
> s = math.sqrt(n)
> TypeError : a float is required
Problem is the new input() function. Yields a string.
Thanks to Scott, Chris, Gabriel & John.
Some thought I was not using the Python 3 command line.
I was : Python 3.0 (r30:67507...
Erratic behavior was that I was sometimes using n = input()
and sometimes entering the integer directly into the
math.sqrt() function, eg s = math.sqrt(4194304)
I cannot find a mention of this in "The Python Tutorial
release 3.1" The I&O section discusses output formatting
and reading & writing text files.
John pointed out its in Guido's "What's New in Python3.0"
Indeed its mentioned in PEP 3111, near end of What's New
and somewhat obscurely. " raw_input() was renamed to input().
That is the new input() function function reads a line from
sys.stdin . . ." Dave Lemper, Texas
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