Recursionerror maximum recursion depth exceeded in comparison in python

Open the Python shell and use the following code to see the value of the recursion limit for the Python interpreter:

>>> import sys >>> print(sys.getrecursionlimit()) 1000 

To increase the recursion limit to 1500 we can add the following lines at the beginning of our program:

import sys sys.setrecursionlimit(1500)

If you do that and try to calculate again the factorial of 1000 you get a long number back (no more errors).

The factorial of 1000 is: 4023872600770937735437024339230039857193748642107146325437999104299385123986290205920 . 835777939410970027753472000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

Modify the “main” of your program as follows:

if __name__ == '__main__': try: print("The factorial of 1000 is: <>".format(factorial(1000))) except RecursionError as re: print("Unable to calculate factorial. Number is too big.") 

You will get the following when calculating the factorial for 1000.

$ python recursion_error.py Unable to calculate factorial. Number is too big. 

Interestingly, if we run our program with Python 2.7 the output is different:

$ python2 recursion_error.py Traceback (most recent call last): File "recursion_error.py", line 13, in except RecursionError as re: NameError: name 'RecursionError' is not defined 

So, if you are using a version of Python older than 3.5 replace the RecursionError with a RuntimeError.

if __name__ == '__main__': try: print("The factorial of 1000 is: <>".format(factorial(1000))) except RuntimeError as re: print("Unable to calculate factorial. Number is too big.") 

In this way our Python application works fine with Python2:

$ python2 recursion_error.py Unable to calculate factorial. Number is too big. 

Let’s look at the function again…

def factorial(n): if n == 0: return 1 else: return n*factorial(n-1) 

We will create a very simple recursive function that doesn’t have an branch breaking the recursion…

def recursive_func(): recursive_func() recursive_func() 

When you run this program you get back “RecursionError: maximum recursion depth exceeded”.

$ python recursion_error2.py Traceback (most recent call last): File "recursion_error2.py", line 4, in recursive_func() File "recursion_error2.py", line 2, in recursive_func recursive_func() File "recursion_error2.py", line 2, in recursive_func recursive_func() File "recursion_error2.py", line 2, in recursive_func recursive_func() [Previous line repeated 996 more times] RecursionError: maximum recursion depth exceeded

We are basically going from recursion to iteration.

def factorial(n): factorial = 1 while n > 0: factorial = factorial*n n = n - 1 return factorial

Our program ends as soon as the factorials calculated by the two functions for a given number don’t match.

def factorial(n): factorial = 1 while n > 0: factorial = factorial*n n = n - 1 return factorial def recursive_factorial(n): if n == 0: return 1 else: return n*factorial(n-1) numbers = [4, 9, 18, 23, 34, 56, 78, 88, 91, 1000] for number in numbers: if factorial(number) != recursive_factorial(number): print("ERROR: The factorials calculated by the two functions for the number <> do not match.".format(number)) print("SUCCESS: The factorials calculated by the two functions match") 

Let’s run our program and see what we get:

$ python factorial.py SUCCESS: The factorials calculated by the two functions match 

Answer by Itzayana McKay

The recursion depth of Python code.,This limit has to the potential to reduce the size of object headers considerably.,The one million limit is mostly a limit on human generated code, not runtime sizes.,The sum of local variables and stack usage for a code object: 3.9 onward.

For example, a super-compact header format might look like this:

Answer by Ricardo Patton

Python's default recursion limit is 1000, meaning that Python won't let a function call on itself more than 1000 times, which for most people is probably enough. The limit exists because allowing recursion to occur more than 1000 times doesn't exactly make for lightweight code. If, however, you find yourself in need of a higher recursion limit, there is a way to override the default limit and reset it to a number of your choice. This isn't exactly recommended, because it can definitely slow your code down, but on the occasion that it needs to be done, here's how you can do it:,What Is Python Programming Used For? Benefits of Python for Business,Let's say you want to set the limit to 1500. All you really need is to set a variable to 1500 followed by one line of code., Add Python to the PATH Environmental Variable (‘python’ is not recognized as an internal or external command)

Let's say you want to set the limit to 1500. All you really need is to set a variable to 1500 followed by one line of code.

import sys x=1500 sys.setrecursionlimit(x)

Answer by Tatum Carpenter

Since the recursion function exceeded the limit of 1000 iterations, recursionerror is thrown.,But if we pass a larger number into the find_fact() function, it will throw RecursionError: Maximum Recursion Depth Exceeded error.,Now, it will not throw any recursion error and simply print the large factorial number.,Now, it will not thrown the recursionerror and the program will be executed for larger amount of recursions. On executing the recursive function, it will not throw any error and print its output.

import sys print(sys.getrecursionlimit()) 

Answer by Nicole Ellison

If the recursion depth exceeds the default maximum recursion depth in Python, it will throw a RecursionError. Let’s see the below example.,This article will introduce methods to get and increase the maximum recursion depth in Python with the getrecursionlimit() and setrecursionlimit() functions.,Use the setrecursionlimit() Function to Set the Maximum Recursion Depth in Python,Use the getrecursionlimit() Function to Get the Maximum Recursion Depth in Python

In Python, we have some limits for recursive functions. It tells about how many times the function will repeat. We can use getrecursionlimit() function to get the maximum recursion depth. The correct syntax is:

The program below shows how we can use this method to get the maximum recursion limit in Python.

import sys print(sys.getrecursionlimit()) 

If the recursion depth exceeds the default maximum recursion depth in Python, it will throw a RecursionError . Let’s see the below example.

def Test(i): if i > 0: return Test(i-1)+1 else: return 0 Test(5000) 

Traceback (most recent call last): File "C:/Test/test.py", line 7, in Test(5000) File "C:/Test/test.py", line 3, in Test return Test(i-1)+1 File "C:/Test/test.py", line 3, in Test return Test(i-1)+1 File "C:/Test/test.py", line 3, in Test return Test(i-1)+1 [Previous line repeated 1021 more times] File "C:/Test/test.py", line 2, in Test if i > 0: RecursionError: maximum recursion depth exceeded in comparison 

We need to increase the maximum recursion depth to solve the above issue. We use setrecursionlimit() function to set the recursion limit. The correct syntax to use this function is as follows:

sys.setrecursionlimit(limit) 

The program below shows how we can use this method to set the recursion limit in Python.

import sys sys.setrecursionlimit(5000) print(sys.getrecursionlimit()) 

Answer by Dakota Day

Recursive function in python,Python change the maximum recursion depth,You can refer to the below screenshot for recursive function in python,You can refer to the below screenshot python recursion list

def factorial(number): if number == 1: return 1 else: return(number * factorial(number - 1)) number = 4 print("Factorial of", number, "is: ", factorial(number))

def sum(number): if number == 1: return 1 else: return(number + sum(number - 1)) number = 6 print("Sum of", number, "is: ", sum(number))

def recursion_fib(num): if num 

import sys print("The current value of the recursion limit:") print(sys.getrecursionlimit())

import sys sys.setrecursionlimit(1006) new_limit = sys.getrecursionlimit() print(new_limit)

def sum(list): if len(list)==0: return 0 else: return list[0]+sum(list[1:]) list = [1,2,3,4,5] print(sum(list))

def fact(num): if num == 0: return 1 else: return num * fact(num-1) print(fact(2000))

import sys sys.setrecursionlimit(4000) def fact(num): if num == 0: return 1 else: return num * fact(num-1) print(fact(2000))