python: checking for errors in the users input -

i check if string can float before attempt convert float. way, if string not float, can print error message , exit instead of crashing program. when user inputs something, wanna see if float print "true" if not print"false" rather crashing. don't want use built in functions this. need make own function this.

i tried : import types

def isfloat():     x = raw_input("enter: ")     if(x) == float:         print("true")      if(x) == str:         print("false")  isfloat() 

i don't know if true or not wont work wont print either

the recommended thing here try it:

try:     f = float(x)     print("true") except valueerror:     # handle error here     print("false") 

this underscores python philosophy "it's better ask forgiveness permission".