[EMAIL PROTECTED] írta:
> Hi,
> I am very new to all this and need to know how to check
> a variable to see if it is a number or not. Also can anyone
> recommend a reference book apart from dive into python
> preferably a reference with good examples of how to impliment
> code.
>
There are different types of number in Python.
Integers and Long integers (type: 'int', 'long')
Decimal numbers (class 'decimal.Decimal')
Floating point numbers (type 'float')
You can check this way:
import decimal
def print_type(var):
if isinstance(var,int):
print "this is an integer"
elif isinstance(var,long):
print "this is a long integer"
elif isinstance(var,decimal.Decimal):
print "this is a decimal"
elif isinstance(var,float):
print "this is a float"
else:
print "this is something else..."
Test this:
...
>>> print_type(12)
this is an integer
>>> print_type(12L)
this is a long integer
>>> print_type(3.5)
this is a float
>>> print_type('hello world')
this is something else...
>>> print_type('44')
this is something else...
>>> d = Decimal('123')
>>> print_type(d)
this is a decimal
>>>
> The project i have been given to work in is all CGI written
> in Python.
>
Probaby you wanted to convert a string into a number? For example:
>>> int(s)
1234
>>> s = 'Foo'
>>> int(s)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
ValueError: invalid literal for int(): Foo
>>>
Or you can catch the exception:
>>> s = 'Foo2'
>>> try:
... intval = int(s)
... except ValueError:
... print "This cannot be converted to an int."
...
This cannot be converted to an int.
>>>
Good luck!
Laszlo
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