fix is_ip_v4_address_valid.py

maths/is_ip_v4_address_valid.py

@@ -1,13 +1,15 @@
 """
+wiki: https://en.wikipedia.org/wiki/IPv4
+
 Is IP v4 address valid?
 A valid IP address must be four octets in the form of A.B.C.D,
-where A,B,C and D are numbers from 0-254
-for example: 192.168.23.1, 172.254.254.254 are valid IP address
-             192.168.255.0, 255.192.3.121 are invalid IP address
+where A, B, C and D are numbers from 0-255
+for example: 192.168.23.1, 172.255.255.255 are valid IP address
+             192.168.256.0, 256.192.3.121 are invalid IP address
 """
 
 
-def is_ip_v4_address_valid(ip_v4_address: str) -> bool:
+def is_ip_v4_address_valid(ip: str) -> bool:
     """
     print "Valid IP address" If IP is valid.
     or
@@ -16,13 +18,13 @@ def is_ip_v4_address_valid(ip_v4_address: str) -> bool:
     >>> is_ip_v4_address_valid("192.168.0.23")
     True
 
-    >>> is_ip_v4_address_valid("192.255.15.8")
+    >>> is_ip_v4_address_valid("192.256.15.8")
     False
 
     >>> is_ip_v4_address_valid("172.100.0.8")
     True
 
-    >>> is_ip_v4_address_valid("254.255.0.255")
+    >>> is_ip_v4_address_valid("255.256.0.256")
     False
 
     >>> is_ip_v4_address_valid("1.2.33333333.4")
@@ -45,12 +47,29 @@ def is_ip_v4_address_valid(ip_v4_address: str) -> bool:
 
     >>> is_ip_v4_address_valid("1.2.3.")
     False
+
+    >>> is_ip_v4_address_valid("1.2.3.05")
+    False
     """
-    octets = [int(i) for i in ip_v4_address.split(".") if i.isdigit()]
-    return len(octets) == 4 and all(0 <= int(octet) <= 254 for octet in octets)
+    octets = ip.split(".")
+    if len(octets) != 4:
+        return False
+
+    for octet in octets:
+        if not octet.isdigit():
+            return False
+
+        number = int(octet)
+        if len(str(number)) != len(octet):
+            return False
+
+        if not 0 <= number <= 255:
+            return False
+
+    return True
 
 
 if __name__ == "__main__":
     ip = input().strip()
     valid_or_invalid = "valid" if is_ip_v4_address_valid(ip) else "invalid"
-    print(f"{ip} is a {valid_or_invalid} IP v4 address.")
+    print(f"{ip} is a {valid_or_invalid} IPv4 address.")