I've been trying to sort an array of number using the sort function but I forgot to write parentheses.
arr.sort
instead of
arr.sort()
My question is why can't python detect this error and inform me like Java can? The program kept compiling fine but because I was inputting the numbers in ascending order, the problem wouldn't show up.
arr.sort is syntactically valid. It's just not the syntax you wanted. Syntactically, arr.sort is an attribute access expression for the sort attribute of whatever arr evaluates to; semantically, when arr is a list, arr.sort evaluates to a method object for arr's sort method, so it's perfectly fine at runtime too.
It's kind of like method references in Java, but since Python is dynamically typed and has method objects, it doesn't need to go through all the functional interface and poly expression stuff Java 8 had to add to support list::sort syntax.
Syntax errors are only for outright invalid syntax.