how to stop a for loop

Question

I\'m writing a code to determine if every element in my nxn list is the same. i.e. [[0,0],[0,0]] returns true but [[0,1],[0,0]] will return false.

Answer 1

In order to jump out of a loop, you need to use the break statement.

n=L[0][0]
m=len(A)
for i in range(m):
 for j in range(m):
   if L[i][j]!=n:
       break;

Here you have the official Python manual with the explanation about break and continue, and other flow control statements:

http://docs.python.org/tutorial/controlflow.html

EDITED: As a commenter pointed out, this does only end the inner loop. If you need to terminate both loops, there is no "easy" way (others have given you a few solutions). One possiblity would be to raise an exception:

def f(L, A):
    try:
        n=L[0][0]
        m=len(A)
        for i in range(m):
             for j in range(m):
                 if L[i][j]!=n:
                     raise RuntimeError( "Not equal" )
        return True
    except:
        return False