split 1234 into ('1', '2', '3', '4')

[ss30]

Hi,

I was wondering if there is a simple way to split 1234 into a string of ('1', '2', '3', '4').

Also, is there a way to test whether an element of a string (or list) is an integer. For instance, if i had a list a = ['1', '2', '3', '4'], the elements are all integers, the function needs to return True.

However, if the list was ['1', '2', '3', 'x'], how would i distinguish that 'x' is not an integer and therefore the function would return False.

So far i have used a for loop:
for i in a:
if int(i) is type(int):
return True
if int(i) is not type(int):
return False

but this isn't working at all.

Thanks for your help :)

[boxfish]

Hi,
The str() function takes an integer argument and returns a string. You can also use the list() and tuple() functions to convert strings to lists and tuples. Your loop has two problems. When it finds a number, it returns true before even checking the other strings. You need to make a loop that quits as soon as it finds a non-number string, and only return true if it goes all the way through the list with no problems. Secondly, int(i) will crash your program with a ValueError if it finds a string that does not convert to an integer. Use this to your advantage. Make a try-except block to detect whether the value is an int or not.
Hope this helps.

[Elias Alhanatis]

Also i would suggest that you'd change your test to:

if type(i) is type(1):
   return True
else:
   return False
 

Elias

[Smygis]

You can do this.

>>> for i in repr(1234):
    if i.isdigit():
        print("OMFG {0} is a digit".format(i))
 
 
OMFG 1 is a digit
OMFG 2 is a digit
OMFG 3 is a digit
OMFG 4 is a digit
>>> 
 

and if we throw in an 'X':

>>> for i in repr(1234)+"X":
    if i.isdigit():
        print("OMFG {0} is a digit".format(i))
    else:
        print("OMFG {0} is not a digit".format(i))
 
 
OMFG 1 is a digit
OMFG 2 is a digit
OMFG 3 is a digit
OMFG 4 is a digit
OMFG X is not a digit
 

You can also use the isinstance function:

>>> isinstance(10, int)
True
>>> isinstance("omg", list)
False
>>> isinstance((), tuple)
True
>>> isinstance("", (list, str, tuple))
True
 

[boxfish]

Also i would suggest that you'd change your test to:

Yes, but that test doesn't work anyway. "1", "2", and "1234" are still strings, so they aren't of type int.

[ghostdog74]

Hi,

I was wondering if there is a simple way to split 1234 into a string of ('1', '2', '3', '4').

>>> a=1234
>>> list(str(a))
['1', '2', '3', '4']
 

Also, is there a way to test whether an element of a string (or list) is an integer. For instance, if i had a list a = ['1', '2', '3', '4'], the elements are all integers, the function needs to return True.

if not [i for i in a if not  i.isdigit()]: print "True"
 

[boxfish]

if not [i for i in a if not i.isdigit()]: print "True"

Wow, that syntax is really wierd. I had no idea you could do that.

[bvdet]

Another possibility:

>>> False not in [c.isdigit() for c in '1234']
True
>>> False not in [c.isdigit() for c in '1234z']
False
>>> 

[boxfish]

If you can do things like that, then what's the map function for?

[ss30]

>>> a=1234
>>> list(str(a))
['1', '2', '3', '4']
 

if not [i for i in a if not  i.isdigit()]: print "True"
 

that's brilliant! and so simple!

Thanks heaps :)

[bvdet]

If you can do things like that, then what's the map function for?

Built-in function map() has largely been replaced by list comprehensions. Example:

map(function, some_list)

is equivalent to:

[function(x) for x in some_list]