Write a function that prints x elements of a list.
Prototype: def safe_print_list(my_list=[], x=0):
my_list can contain any type (integer, string, etc.)
All elements must be printed on the same line followed by a new line.
x represents the number of elements to print
x can be bigger than the length of my_list
Returns the real number of elements printed
You have to use try: / except:
You are not allowed to import any module
You are not allowed to use len()
guillaume@ubuntu:~/0x05$ cat 0-main.py
#!/usr/bin/python3
safe_print_list = __import__('0-safe_print_list').safe_print_list
my_list = [1, 2, 3, 4, 5]
nb_print = safe_print_list(my_list, 2)
print("nb_print: {:d}".format(nb_print))
nb_print = safe_print_list(my_list, len(my_list))
print("nb_print: {:d}".format(nb_print))
nb_print = safe_print_list(my_list, len(my_list) + 2)
print("nb_print: {:d}".format(nb_print))
guillaume@ubuntu:~/0x05$ ./0-main.py
12
nb_print: 2
12345
nb_print: 5
12345
nb_print: 5
guillaume@ubuntu:~/0x05$
Write a function that prints an integer with "{:d}".format().
Prototype: def safe_print_integer(value):
value can be any type (integer, string, etc.)
The integer should be printed followed by a new line
Returns True if value has been correctly printed (it means the value is an integer)
Otherwise, returns False
You have to use try: / except:
You have to use "{:d}".format() to print as integer
You are not allowed to import any module
You are not allowed to use type()
guillaume@ubuntu:~/0x05$ cat 1-main.py
#!/usr/bin/python3
safe_print_integer = __import__('1-safe_print_integer').safe_print_integer
value = 89
has_been_print = safe_print_integer(value)
if not has_been_print:
print("{} is not an integer".format(value))
value = -89
has_been_print = safe_print_integer(value)
if not has_been_print:
print("{} is not an integer".format(value))
value = "School"
has_been_print = safe_print_integer(value)
if not has_been_print:
print("{} is not an integer".format(value))
guillaume@ubuntu:~/0x05$ ./1-main.py
89
-89
School is not an integer
guillaume@ubuntu:~/0x05$
Write a function that prints the first x elements of a list and only integers.
Prototype: def safe_print_list_integers(my_list=[], x=0):
my_list can contain any type (integer, string, etc.)
All integers have to be printed on the same line followed by a new line - other type of value in the list must be skipped (in silence).
x represents the number of elements to access in my_list
x can be bigger than the length of my_list - if it’s the case, an exception is expected to occur
Returns the real number of integers printed
You have to use try: / except:
You have to use "{:d}".format() to print an integer
You are not allowed to import any module
You are not allowed to use len()
guillaume@ubuntu:~/0x05$ cat 2-main.py
#!/usr/bin/python3
safe_print_list_integers = \
__import__('2-safe_print_list_integers').safe_print_list_integers
my_list = [1, 2, 3, 4, 5]
nb_print = safe_print_list_integers(my_list, 2)
print("nb_print: {:d}".format(nb_print))
my_list = [1, 2, 3, "School", 4, 5, [1, 2, 3]]
nb_print = safe_print_list_integers(my_list, len(my_list))
print("nb_print: {:d}".format(nb_print))
nb_print = safe_print_list_integers(my_list, len(my_list) + 2)
print("nb_print: {:d}".format(nb_print))
guillaume@ubuntu:~/0x05$ ./2-main.py
12
nb_print: 2
12345
nb_print: 5
12345Traceback (most recent call last):
File "./2-main.py", line 14, in <module>
nb_print = safe_print_list_integers(my_list, len(my_list) + 2)
File "/0x05/2-safe_print_list_integers.py", line 7, in safe_print_list_integers
print("{:d}".format(my_list[i]), end="")
IndexError: list index out of range
guillaume@ubuntu:~/0x05$
Write a function that divides 2 integers and prints the result.
Prototype: def safe_print_division(a, b):
You can assume that a and b are integers
The result of the division should print on the finally: section preceded by Inside result:
Returns the value of the division, otherwise: None
You have to use try: / except: / finally:
You have to use "{}".format() to print the result
You are not allowed to import any module
guillaume@ubuntu:~/0x05$ cat 3-main.py
#!/usr/bin/python3
safe_print_division = __import__('3-safe_print_division').safe_print_division
a = 12
b = 2
result = safe_print_division(a, b)
print("{:d} / {:d} = {}".format(a, b, result))
a = 12
b = 0
result = safe_print_division(a, b)
print("{:d} / {:d} = {}".format(a, b, result))
guillaume@ubuntu:~/0x05$ ./3-main.py
Inside result: 6.0
12 / 2 = 6.0
Inside result: None
12 / 0 = None
guillaume@ubuntu:~/0x05$
Write a function that divides element by element 2 lists.
Prototype: def list_division(my_list_1, my_list_2, list_length):
my_list_1 and my_list_2 can contain any type (integer, string, etc.)
list_length can be bigger than the length of both lists
Returns a new list (length = list_length) with all divisions
If 2 elements can’t be divided, the division result should be equal to 0
If an element is not an integer or float:
print: wrong type
If the division can’t be done (/0):
print: division by 0
If my_list_1 or my_list_2 is too short
print: out of range
You have to use try: / except: / finally:
You are not allowed to import any module
guillaume@ubuntu:~/0x05$ cat 4-main.py
#!/usr/bin/python3
list_division = __import__('4-list_division').list_division
my_l_1 = [10, 8, 4]
my_l_2 = [2, 4, 4]
result = list_division(my_l_1, my_l_2, max(len(my_l_1), len(my_l_2)))
print(result)
print("--")
my_l_1 = [10, 8, 4, 4]
my_l_2 = [2, 0, "H", 2, 7]
result = list_division(my_l_1, my_l_2, max(len(my_l_1), len(my_l_2)))
print(result)
guillaume@ubuntu:~/0x05$ ./4-main.py
[5.0, 2.0, 1.0]
--
division by 0
wrong type
out of range
[5.0, 0, 0, 2.0, 0]
guillaume@ubuntu:~/0x05$
Write a function that raises a type exception.
Prototype: def raise_exception():
You are not allowed to import any module
guillaume@ubuntu:~/0x05$ cat 5-main.py
#!/usr/bin/python3
raise_exception = __import__('5-raise_exception').raise_exception
try:
raise_exception()
except TypeError as te:
print("Exception raised")
guillaume@ubuntu:~/0x05$ ./5-main.py
Exception raised
guillaume@ubuntu:~/0x05$
Write a function that raises a name exception with a message.
Prototype: def raise_exception_msg(message=""):
You are not allowed to import any module
guillaume@ubuntu:~/0x05$ cat 6-main.py
#!/usr/bin/python3
raise_exception_msg = __import__('6-raise_exception_msg').raise_exception_msg
try:
raise_exception_msg("C is fun")
except NameError as ne:
print(ne)
guillaume@ubuntu:~/0x05$ ./6-main.py
C is fun
guillaume@ubuntu:~/0x05$
Write a function that prints an integer.
Prototype: def safe_print_integer_err(value):
value can be any type (integer, string, etc.)
The integer should be printed followed by a new line
Returns True if value has been correctly printed (it means the value is an integer)
Otherwise, returns False and prints in stderr the error precede by Exception:
You have to use try: / except:
You have to use "{:d}".format() to print as integer
You are not allowed to use type()
guillaume@ubuntu:~/0x05$ cat 100-main.py
#!/usr/bin/python3
safe_print_integer_err = \
__import__('100-safe_print_integer_err').safe_print_integer_err
value = 89
has_been_print = safe_print_integer_err(value)
if not has_been_print:
print("{} is not an integer".format(value))
value = -89
has_been_print = safe_print_integer_err(value)
if not has_been_print:
print("{} is not an integer".format(value))
value = "School"
has_been_print = safe_print_integer_err(value)
if not has_been_print:
print("{} is not an integer".format(value))
guillaume@ubuntu:~/0x05$ ./100-main.py
89
-89
Exception: Unknown format code 'd' for object of type 'str'
School is not an integer
guillaume@ubuntu:~/0x05$ ./100-main.py 2> /dev/null
89
-89
School is not an integer
guillaume@ubuntu:~/0x05$
Write a function that executes a function safely.
Prototype: def safe_function(fct, *args):
You can assume fct will be always a pointer to a function
Returns the result of the function,
Otherwise, returns None if something happens during the function and prints in stderr the error precede by Exception:
You have to use try: / except:
guillaume@ubuntu:~/0x05$ cat 101-main.py
#!/usr/bin/python3
safe_function = __import__('101-safe_function').safe_function
def my_div(a, b):
return a / b
result = safe_function(my_div, 10, 2)
print("result of my_div: {}".format(result))
result = safe_function(my_div, 10, 0)
print("result of my_div: {}".format(result))
def print_list(my_list, len):
i = 0
while i < len:
print(my_list[i])
i += 1
return len
result = safe_function(print_list, [1, 2, 3, 4], 10)
print("result of print_list: {}".format(result))
guillaume@ubuntu:~/0x05$ ./101-main.py
result of my_div: 5.0
Exception: division by zero
result of my_div: None
1
2
3
4
Exception: list index out of range
result of print_list: None
guillaume@ubuntu:~/0x05$ ./101-main.py 2> /dev/null
result of my_div: 5.0
result of my_div: None
1
2
3
4
result of print_list: None
guillaume@ubuntu:~/0x05$
Write the Python function def magic_calculation(a, b): that does exactly the same as the following Python bytecode:
3 0 LOAD_CONST 1 (0)
3 STORE_FAST 2 (result)
4 6 SETUP_LOOP 94 (to 103)
9 LOAD_GLOBAL 0 (range)
12 LOAD_CONST 2 (1)
15 LOAD_CONST 3 (3)
18 CALL_FUNCTION 2 (2 positional, 0 keyword pair)
21 GET_ITER
>> 22 FOR_ITER 77 (to 102)
25 STORE_FAST 3 (i)
5 28 SETUP_EXCEPT 49 (to 80)
6 31 LOAD_FAST 3 (i)
34 LOAD_FAST 0 (a)
37 COMPARE_OP 4 (>)
40 POP_JUMP_IF_FALSE 58
7 43 LOAD_GLOBAL 1 (Exception)
46 LOAD_CONST 4 ('Too far')
49 CALL_FUNCTION 1 (1 positional, 0 keyword pair)
52 RAISE_VARARGS 1
55 JUMP_FORWARD 18 (to 76)
9 >> 58 LOAD_FAST 2 (result)
61 LOAD_FAST 0 (a)
64 LOAD_FAST 1 (b)
67 BINARY_POWER
68 LOAD_FAST 3 (i)
71 BINARY_TRUE_DIVIDE
72 INPLACE_ADD
73 STORE_FAST 2 (result)
>> 76 POP_BLOCK
77 JUMP_ABSOLUTE 22
10 >> 80 POP_TOP
81 POP_TOP
82 POP_TOP
11 83 LOAD_FAST 1 (b)
86 LOAD_FAST 0 (a)
89 BINARY_ADD
90 STORE_FAST 2 (result)
12 93 BREAK_LOOP
94 POP_EXCEPT
95 JUMP_ABSOLUTE 22
98 END_FINALLY
99 JUMP_ABSOLUTE 22
>> 102 POP_BLOCK
13 >> 103 LOAD_FAST 2 (result)
106 RETURN_VALUE
Create three C functions that print some basic info about Python lists, Python bytes an Python float objects.
Python lists: Prototype: void print_python_list(PyObject *p); Format: see example If p is not a valid PyListObject, print an error message (see example)
Python bytes:
Prototype: void print_python_bytes(PyObject *p);
Format: see example
Line “first X bytes”: print a maximum of 10 bytes
If p is not a valid PyBytesObject, print an error message (see example)
Python float:
Prototype: void print_python_float(PyObject *p);
Format: see example
If p is not a valid PyFloatObject, print an error message (see example)
Read /usr/include/python3.4/floatobject.h
About:
Python version: 3.4
You are allowed to use the C standard library
Your shared library will be compiled with this command line: gcc -Wall -Werror -Wextra -pedantic -std=c99 -shared -Wl,-soname,libPython.so -o libPython.so -fPIC -I/usr/include/python3.4 103-python.c
You are not allowed to use the following macros/functions:
Py_SIZE
Py_TYPE
PyList_Size
PyList_GetItem
PyBytes_AS_STRING
PyBytes_GET_SIZE
PyBytes_AsString
PyBytes_AsStringAndSize
PyFloat_AS_DOUBLE
PySequence_GetItem
PySequence_Fast_GET_SIZE
PySequence_Fast_GET_ITEM
PySequence_ITEM
PySequence_Fast_ITEMS
NOTE:
The python script will be launched using the -u option (Force stdout to be unbuffered).
It is strongly advised to either use setbuf(stdout, NULL); or fflush(stdout) in your C functions IF you choose to use printf. The reason to that is that Pythonsprintand libCs printf don’t share the same buffer, and the output can appear disordered.
julien@ubuntu:~/CPython$ python3 --version
Python 3.4.3
julien@ubuntu:~/CPython$ gcc -Wall -Werror -Wextra -pedantic -std=c99 -shared -Wl,-soname,libPython.so -o libPython.so -fPIC -I/usr/include/python3.4 103-python.c
julien@ubuntu:~/CPython$ cat 103-tests.py
#!/usr/bin/python3 -u
import ctypes
lib = ctypes.CDLL('./libPython.so')
lib.print_python_list.argtypes = [ctypes.py_object]
lib.print_python_bytes.argtypes = [ctypes.py_object]
lib.print_python_float.argtypes = [ctypes.py_object]
s = b"Hello"
lib.print_python_bytes(s);
b = b'\xff\xf8\x00\x00\x00\x00\x00\x00';
lib.print_python_bytes(b);
b = b'What does the \'b\' character do in front of a string literal?';
lib.print_python_bytes(b);
l = [b'Hello', b'World']
lib.print_python_list(l)
del l[1]
lib.print_python_list(l)
l = l + [4, 5, 6.0, (9, 8), [9, 8, 1024], b"School", "Betty"]
lib.print_python_list(l)
l = []
lib.print_python_list(l)
l.append(0)
lib.print_python_list(l)
l.append(1)
l.append(2)
l.append(3)
l.append(4)
lib.print_python_list(l)
l.pop()
lib.print_python_list(l)
l = ["School"]
lib.print_python_list(l)
lib.print_python_bytes(l);
f = 3.14
lib.print_python_float(f);
l = [-1.0, -0.1, 0.0, 1.0, 3.14, 3.14159, 3.14159265, 3.141592653589793238462643383279502884197169399375105820974944592307816406286]
print(l)
lib.print_python_list(l);
lib.print_python_float(l);
lib.print_python_list(f);
julien@ubuntu:~/CPython$ ./103-tests.py
[.] bytes object info
size: 5
trying string: Hello
first 6 bytes: 48 65 6c 6c 6f 00
[.] bytes object info
size: 8
trying string: ??
first 9 bytes: ff f8 00 00 00 00 00 00 00
[.] bytes object info
size: 60
trying string: What does the 'b' character do in front of a string literal?
first 10 bytes: 57 68 61 74 20 64 6f 65 73 20
[*] Python list info
[*] Size of the Python List = 2
[*] Allocated = 2
Element 0: bytes
[.] bytes object info
size: 5
trying string: Hello
first 6 bytes: 48 65 6c 6c 6f 00
Element 1: bytes
[.] bytes object info
size: 5
trying string: World
first 6 bytes: 57 6f 72 6c 64 00
[*] Python list info
[*] Size of the Python List = 1
[*] Allocated = 2
Element 0: bytes
[.] bytes object info
size: 5
trying string: Hello
first 6 bytes: 48 65 6c 6c 6f 00
[*] Python list info
[*] Size of the Python List = 8
[*] Allocated = 8
Element 0: bytes
[.] bytes object info
size: 5
trying string: Hello
first 6 bytes: 48 65 6c 6c 6f 00
Element 1: int
Element 2: int
Element 3: float
[.] float object info
value: 6.0
Element 4: tuple
Element 5: list
Element 6: bytes
[.] bytes object info
size: 9
trying string: School
first 10 bytes: 48 6f 6c 62 65 72 74 6f 6e 00
Element 7: str
[*] Python list info
[*] Size of the Python List = 0
[*] Allocated = 0
[*] Python list info
[*] Size of the Python List = 1
[*] Allocated = 4
Element 0: int
[*] Python list info
[*] Size of the Python List = 5
[*] Allocated = 8
Element 0: int
Element 1: int
Element 2: int
Element 3: int
Element 4: int
[*] Python list info
[*] Size of the Python List = 4
[*] Allocated = 8
Element 0: int
Element 1: int
Element 2: int
Element 3: int
[*] Python list info
[*] Size of the Python List = 1
[*] Allocated = 1
Element 0: str
[.] bytes object info
[ERROR] Invalid Bytes Object
[.] float object info
value: 3.14
[-1.0, -0.1, 0.0, 1.0, 3.14, 3.14159, 3.14159265, 3.141592653589793]
[*] Python list info
[*] Size of the Python List = 8
[*] Allocated = 8
Element 0: float
[.] float object info
value: -1.0
Element 1: float
[.] float object info
value: -0.1
Element 2: float
[.] float object info
value: 0.0
Element 3: float
[.] float object info
value: 1.0
Element 4: float
[.] float object info
value: 3.14
Element 5: float
[.] float object info
value: 3.14159
Element 6: float
[.] float object info
value: 3.14159265
Element 7: float
[.] float object info
value: 3.141592653589793
[.] float object info
[ERROR] Invalid Float Object
[*] Python list info
[ERROR] Invalid List Object
julien@ubuntu:~/CPython$