Python integer issues

Question

EDIT: SOLVED--SOURCE CODE HERE: http://matthewdowney20.blogspot.com/2011/09/source-code-for-roku-remote-hack.html

thanks in advance for reading and possibly answering this. So I have a slice of code that looks like this (the commands Down() Select() and Up() are all predefined):

def c1(row):
   row_down = row
   row_up = row
   while row_down > '1':
       Down()
       row_down = row_down - 1
       time.sleep(250)
   Select()
   time.sleep(.250)
   while row_up > '1':
       Up()
       row_up = row_up - 1
       time.sleep(250)

So when I run this with either c1('3') or c1(3) (not jut 3, any number does this) it stops responding, no error or anything, but it executes the first Down() command, and it doesnt seem to get past the row_down = row_down - 1 . So i figure maybe it is stuck on time.sleep(.250), because it isnt executing the Select(), so if i remove time.sleep(.250) from the code i get an error like this:

Traceback (most recent call last):
  File "test.py", line 338, in <module>
    c1('3')
  File "test.py", line 206, in c1
    row_down = row_down - 1
TypeError: unsupported operand type(s) for -: 'str' and 'int'

this code snippet is part of a larger program designed for controlling the roku player from a computer, and so far everything has worked but this, which is to automate the typing in the search field, so that you do not have to continually scroll until you find a letter and select. c1(row) would be column 1 row x, if any of you would like the source code for the program over all, i would be happy to send it out. Anyway thanks for listening.

I can see what the problem is, but You haven't given us enough information to give you a *helpful* answer. How does `row` get set, what do `Up()`, `Down()`, and `Select()` really do? — SingleNegationElimination, Sep 11 '11 at 01:13
@user802303: Python is strongly-typed. It won't treat strings as integers. Also, `time.sleep` works on seconds, so the first one sleeps for 250 seconds. — Marcelo Cantos, Sep 11 '11 at 01:14
@TokenMacGuy: `row` is the parameter, and I suspect it doesn't matter what the functions do. — Marcelo Cantos, Sep 11 '11 at 01:15

score 4 · Accepted Answer · edited May 23 '17 at 12:12

4

Perhaps you meant

while row_down > 1:

(note 1 is written without quotes). If so, call c1 with c1(3) not c1('3').

Also, in CPython (version 2, but not version 3) integers are comparable to strings, but the answer is not what you might expect:

3 > '1'
# False

When comparing any integer to any string, the integer is always less than string because (believe it or not!) i (as in integer) comes before s (as in string) in the alphabet.

As TokenMacGuy has already pointed out, addition of integers with strings raises a TypeError:

'3' - 1
# TypeError: unsupported operand type(s) for +: 'int' and 'str'

This might explain the error you are seeing when calling c1('3').

edited May 23 '17 at 12:12

Community

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answered Sep 11 '11 at 01:21

unutbu

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Thanks, this totally helped me debug it! – John Dorian Sep 11 '11 at 17:22
Source Code Here: http://matthewdowney20.blogspot.com/2011/09/source-code-for-roku-remote-hack.html – John Dorian Sep 11 '11 at 18:01

score 1 · Answer 2 · answered Sep 11 '11 at 01:20

>>> x = raw_input('enter a number: ')
enter a number: 5
>>> x
'5'
>>> type(x)
<type 'str'>
>>> x + 5
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: cannot concatenate 'str' and 'int' objects
>>> type(int(x))
<type 'int'>
>>> int(x) + 5
10
>>>

(if you're using python3, use input instead of raw_input)

randrumree · Answer 3 · 2011-09-11T06:59:53.490

I suspect that the loop is running with out error because you can subtract from a character to change it: "b - 1 = a". (read edit) It also doesn't error is because, like Marcelo Cantos said in his comment, the first time.sleep is for 250 seconds, not .250 seconds. The error when you remove the time.sleep might be coming up when you subtract past the the ASCII character range since it runs through the loop a lot quicker without the time.sleep.

I hope that helps!

Edit: Actually, I think what I said works in C or something. In python, it doesn't work. The other stuff I said might shed some light though!

Python integer issues

3 Answers3