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  I was thinking of writing a code that stops immediately when it finds an element that is not the same as the first element  i e   n L 0  0  m len A  for i in range m    for j in range m      if     L i  j   n  -continue the loop-    else  -stop the loop-   I would like to stop this loop if L i  j    n  and return false  otherwise return true  How would I go about implementing this

User · Answer

To stop your loop you can use break with label  It will stop your loop for sure  Code is written in Java but aproach is the same for the all languages    public void exitFromTheLoop         boolean value   true              loop label for  int i   0  i  lt  10  i                    if  value                      System out println  iteration      i                 break loop label

User · Answer

To achieve this you would do something like   n L 0  0  m len A  for i in range m       for j in range m           if L i  j   n                do some processing         else              break

User · Answer

Use break and continue to do this  Breaking nested loops can be done in Python using the following   for a in range          for b in range            if some condition             break the inner loop          break    else          will be called if the previous loop did not end with a  break         continue      but here we end up right after breaking the inner loop  so we can      simply break the outer loop as well    break   Another way is to wrap everything in a function and use return to escape from the loop

User · Answer

Others ways to do the same is   el   L 0  0  m len L   print L      el  m  m   Or   first el   L 0  0  print all el    first el for inner list in L for el in inner list

User · Answer

Use the break statement  http   docs python org reference simple stmts html break

User · Answer

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

User · Answer

There are several ways to do it   The simple Way  a sentinel variable  n   L 0  0  m   len A  found   False for i in range m      if found        break    for j in range m        if L i  j     n          found   True        break   Pros  easy to understand Cons  additional conditional statement for every loop  The hacky Way  raising an exception  n   L 0  0  m   len A   try    for x in range 3       for z in range 3        if L i  j     n          raise StopIteration except StopIteration     pass   Pros  very straightforward Cons  you use Exception outside of their semantic  The clean Way  make a function  def is different value l  elem  size     for x in range size       for z in range size        if l i  j     elem          return True   return False  if is different value L  L 0  0   len A      print  Doh    pros  much cleaner and still efficient cons  yet feels like C  The pythonic way  use iteration as it should be  def is different value iterable     first   iterable 0  0    for l in iterable      for elem in l         if elem    first             return True   return False  if is different value L     print  Doh    pros  still clean and efficient cons  you reinvdent the wheel  The guru way  use any     def is different value iterable     first   iterable 0  0    return  any any  cell    first for cell in col   for elem in iterable     if is different value L     print  Doh    pros  you ll feel empowered with dark powers cons  people that will read you code may start to dislike you

User · Answer

Try to simply use break statement   Also you can use the following code as an example   a     0 1 0    1 0 0    1 1 1   b     0 0 0    0 0 0    0 0 0    def check matr matr  expVal           for row in matr          if len set row    gt  1 or set row  pop      expVal              print  Wrong              break  or return         else              print  ok      else          print  empty  check matr a  0  check matr b  0

[python] how to stop a for loop

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