Re: check to see if value can be an integer instead of string
Thanks guys, No, i did not know about isdigit ? very helpful. Thanks. esp liked the overloaded doohicky' bit. thanks again. -- http://mail.python.org/mailman/listinfo/python-list
Re: check to see if value can be an integer instead of string
On Tue, 17 Jan 2006 18:02:52 -0800, nephish wrote: Hello there, i need a way to check to see if a certain value can be an integer. I have looked at is int(), but what is comming out is a string that may be an integer. Not in Python it isn't. int(value) returns an int, not a string. i mean, it will be formatted as a string, but i need to know if it is possible to be expressed as an integer. like this var = some var passed to my script if var can be an integer : do this else: change it to an integer and do something else with it. So, let's see if I understand your problem: if var can be an integer, you do this (whatever this is). If var *can't* be an integer, you change it to an integer anyway. whats the best way to do this ? try: int(var) except ValueError: raise else: do_this() Or even simpler: int(var) do_this() -- Steven. -- http://mail.python.org/mailman/listinfo/python-list
Re: check to see if value can be an integer instead of string
it isn't really that i will want to change it to an integer anyway. the script uses a table to reference a value to a key, if the key is a group of letters, that code tells the script to do something. if the value is a number, it means an equipment failure. The thing is, all the values come out as strings (they are read from a text file). so what you put first with the try/except looks like my best answer. thanks, shawn -- http://mail.python.org/mailman/listinfo/python-list
Re: check to see if value can be an integer instead of string
[EMAIL PROTECTED] wrote: it isn't really that i will want to change it to an integer anyway. the script uses a table to reference a value to a key, if the key is a group of letters, that code tells the script to do something. if the value is a number, it means an equipment failure. The thing is, all the values come out as strings (they are read from a text file). so what you put first with the try/except looks like my best answer. thanks, shawn Shawn Are you aware of the string method 'isdigit()' ? vars = [KEY_ONE, KEY_2, 0, 1, 24, 00100] for var in vars: if not var.isdigit(): print OPTION: %s % var else: print EQUIPMENT FAILURE: %s % var OPTION: KEY_ONE OPTION: KEY_2 EQUIPMENT FAILURE: 0 EQUIPMENT FAILURE: 1 EQUIPMENT FAILURE: 24 EQUIPMENT FAILURE: 00100 ( 'isdigit' != 'is_a_digit' rather 'isdigit' == 'is_a_string_of_digits' ) Gerard -- http://mail.python.org/mailman/listinfo/python-list
Re: check to see if value can be an integer instead of string
On Wed, 18 Jan 2006 04:23:17 -0800, nephish wrote:
it isn't really that i will want to change it to an integer anyway. the
script uses a table to reference a value to a key, if the key is a
group of letters, that code tells the script to do something. if the
value is a number, it means an equipment failure. The thing is, all the
values come out as strings (they are read from a text file).
so what you put first with the try/except looks like my best answer.
def do_this():
print Do this
def do_that():
print Doing something else
code_table = { abc: do_this, def: do_that, xyz: do_this }
error_table = { 001: Broken widget, 002: Overloaded doohickey}
if code_table.has_key(value_from_hardware):
code_table[value_from_hardware]()
else:
try:
print error_table[value_from_hardware]
except KeyError:
raise CustomHardwareError(Unknown value!)
--
Steven.
--
http://mail.python.org/mailman/listinfo/python-list
check to see if value can be an integer instead of string
Hello there, i need a way to check to see if a certain value can be an integer. I have looked at is int(), but what is comming out is a string that may be an integer. i mean, it will be formatted as a string, but i need to know if it is possible to be expressed as an integer. like this var = some var passed to my script if var can be an integer : do this else: change it to an integer and do something else with it. whats the best way to do this ? thanks, shawn -- http://mail.python.org/mailman/listinfo/python-list
Re: check to see if value can be an integer instead of string
[EMAIL PROTECTED] wrote: Hello there, i need a way to check to see if a certain value can be an integer. I have looked at is int(), but what is comming out is a string that may be an integer. i mean, it will be formatted as a string, but i need to know if it is possible to be expressed as an integer. like this var = some var passed to my script if var can be an integer : do this else: change it to an integer and do something else with it. whats the best way to do this ? thanks, shawn No idea whats the best way to do and what in detail you want to achieve, but before others reply here, you can maybe start with something like this: intTheInt = None def checkIfStringCanBeAnInteger(strWithInt): global intTheInt try: intTheInt = int(strWithInt) if(type(intTheInt)==type(1)): return True except: return False #:def lstTestCases = [ '123', '789' , 'no', '1is2' ] for strWithInt in lstTestCases: intTheInt = None if checkIfStringCanBeAnInteger(strWithInt): print ''+strWithInt+'', ' is an integer', intTheInt else: print ''+strWithInt+'', ' is NOT an integer' Claudio -- http://mail.python.org/mailman/listinfo/python-list
Re: check to see if value can be an integer instead of string
thanks for the reply, but wont python fail out if you try to make an integer out of what cant be an integer? like this : var = int(abc) wont this crash ? -- http://mail.python.org/mailman/listinfo/python-list
Re: check to see if value can be an integer instead of string
Python uses Exceptions to catch these Exceptional situations:http://docs.python.org/tut/node10.html -Brian Cole On 17 Jan 2006 18:51:44 -0800, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: thanks for the reply, but wont python fail out if you try to make an integer out of what cant be an integer? like this : var = int(abc) wont this crash ? -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: check to see if value can be an integer instead of string
[EMAIL PROTECTED] wrote: Hello there, i need a way to check to see if a certain value can be an integer. I have looked at is int(), but what is comming out is a string that may be an integer. i mean, it will be formatted as a string, but i need to know if it is possible to be expressed as an integer. The int builtin function never returns any value but an integer. like this var = some var passed to my script if var can be an integer : do this else: change it to an integer and do something else with it. Be careful about thinking change it to an integer in python. That's not what happens. The int builtin function looks at it's argument and, if possible, creates a new integer object that it thinks was represented by the argument, and returns that integer object. whats the best way to do this ? The pythonic way might be something like: var=somestring try: do_something(int(var)) #just try to convert var to integer and proceed except ValueError: do_something_else(var) # conversion failed; do something with the raw string value The int builtin function tries to make an integer based on whatever argument is supplied. If if can not make an integer from the argument, it raises a ValueError exception. Don't be afraid of using exceptions in this sort of situation. They are pretty fast, and ultimately clearer than a lot of extra if tests. But do please always (unless you *really*really* know what you're doing!) use a qualified except clause. E.g. try: stuff except SomeParticularException: other_stuff Not: try: stuff except: other_stuff The bare except clause invites all kinds of silent, unexpected bad behavior. -- http://mail.python.org/mailman/listinfo/python-list
Re: check to see if value can be an integer instead of string
this looks like the solution i am looking for. thanks for the education by the way. i have a couple of other try / except clauses. Never thought of pulling it off like that. thanks very much, really simple. -- http://mail.python.org/mailman/listinfo/python-list
