Python3 : Fail to raise TypeError

Question

I'd like to raise a TypeError when the parameter of a method in a class is non-integer, but I failed. The code is as below, I put a "N" in the first parameter and expected to get a TypeError, and the printing of " can't set the Rectangle to a non-integer value ", but what I got instead is "Traceback (most recent call last): File "/Users/Janet/Documents/module6.py", line 19, in r1.setData(N,5) NameError: name 'N' is not defined"

class Rectangle:
    def __init__ (self):
        self.height = 0
        self.width = 0

    def setData(self, height, width):
        if type(height) != int or type(width) != int:
        raise TypeError()
        if height <0 or width <0:
        raise ValueError()
        self.height = height
        self.width = width

    def __str__(self):
        return "height = %i, and width = %i" % (self.height, self.width)

r1 = Rectangle()
try:
   r1.setData(N,5)
except ValueError:
   print ("can't set the Rectangle to a negative number")
except TypeError:
   print ("can't set the Rectangle to a non-integer value")

print (r1)

Please indent your code correctly, and tell us what is actually happening. — donkopotamus, May 09 '16 at 23:11
@donkopotamus thanks for reminding, I've rewrite my question and code. — Shengjing, May 10 '16 at 00:07
@Evert It's the string I use for testing purpose in order to get the TypeError printing — Shengjing, May 10 '16 at 00:09
`N` by itself is (the name of) a variable (which you didn't define, hence the error you're getting). If you use in `"N"` (a string) instead, you'll get your TypeError. — , May 10 '16 at 06:25

score 0 · Answer 1 · edited May 23 '17 at 11:44

0

Consider using typeof, as in this question: Checking whether a variable is an integer or not

You have some bad formatting in your listing, by the way. Change this:

def setData(self, height, width):
    if type(height) != int or type(width) != int:
    raise TypeError()
    if height <0 or width <0:
    raise ValueError()
    self.height = height
    self.width = width

to this:

def setData(self, height, width):
    if type(height) != int or type(width) != int:
        raise TypeError()
    if height <0 or width <0:
        raise ValueError()
    self.height = height
    self.width = width

edited May 23 '17 at 11:44

Community

1
1

answered May 09 '16 at 23:13

mark-henry

11
4

1

Did you mean `isinstance`? Although that would cover classes inheriting from `int`, it likely won't solve OP's problem. – tdelaney May 09 '16 at 23:35

Sisoma Munden · Accepted Answer · 2016-05-10T16:25:15.697

Edit answer to reflect the new and more accurate explanation. As @Evert says, N is not defined, so Python is looking what the variable N is, and it isn't finding anything. If you instead wrote "N" (making it a string), then your program should return TypeError.

class Rectangle:
    def __init__ (self):
        self.height = 0
        self.width = 0

    def setData(self, height, width):
        if type(height) != int or type(width) != int:
            raise TypeError()
        if height <0 or width <0:
            raise ValueError()
            self.height = height
            self.width = width

    def __str__(self):
        return "height = %i, and width = %i" % (self.height, self.width)

r1 = Rectangle()
try:
       r1.setData("N",5)
except ValueError:
   print ("can't set the Rectangle to a negative number")
except TypeError:
   print ("can't set the Rectangle to a non-integer value")

print (r1)

This prints out: "can't set the Rectangle to a non-integer value height = 0, and width = 0"

This is more appropriately a "cannot reproduce" comment than an answer. — tdelaney, May 09 '16 at 23:33

Python3 : Fail to raise TypeError

2 Answers2