Python Interview Question Set 2
Categories: Python
What is zip() function in Python?
Python zip() function returns a zip object, which maps a similar index of multiple containers. It takes an iterable, convert into iterator and aggregates the elements based on iterables passed. It returns an iterator of tuples.
Signature
zip(iterator1, iterator2, iterator3 ...)
Parameters
iterator1, iterator2, iterator3: These are iterator objects that are joined together.
Return
It returns an iterator from two or more iterators.
What is Python's parameter passing mechanism?
There are two parameters passing mechanism in Python:
Pass by references
Pass by value
By default, all the parameters (arguments) are passed "by reference" to the functions. Thus, if you change the value of the parameter within a function, the change is reflected in the calling function as well. It indicates the original variable. For example, if a variable is declared as a = 10, and passed to a function where it's value is modified to a = 20. Both the variables denote to the same value.
How to overload constructors or methods in Python?
Python's constructor: _init__ () is the first method of a class. Whenever we try to instantiate an object __init__() is automatically invoked by python to initialize members of an object. We can't overload constructors or methods in Python. It shows an error if we try to overload.
What is the difference between remove() function and del statement?
The user can use the remove() function to delete a specific object in the list.
Example:
list_1 = [ 3, 5, 7, 3, 9, 3 ]
print(list_1)
list_1.remove(3)
print("After removal: ", list_1)
Output:
[3, 5, 7, 3, 9, 3]
After removal: [5, 7, 3, 9, 3]
What is swapcase() function in the Python?
It is a string's function which converts all uppercase characters into lowercase and vice versa. It is used to alter the existing case of the string. This method creates a copy of the string which contains all the characters in the swap case. If the string is in lowercase, it generates a small case string and vice versa. It automatically ignores all the non-alphabetic characters. See an example below.
Example:
string = "IT IS IN LOWERCASE."
print(string.swapcase())
string = "it is in uppercase."
print(string.swapcase())
Output:
it is in lowercase.
IT IS IN UPPERCASE.
How to remove whitespaces from a string in Python?
To remove the whitespaces and trailing spaces from the string, Python providies strip([str]) built-in function. This function returns a copy of the string after removing whitespaces if present. Otherwise returns original string.
How to remove leading whitespaces from a string in the Python?
To remove leading characters from a string, we can use lstrip() function. It is Python string function which takes an optional char type parameter. If a parameter is provided, it removes the character. Otherwise, it removes all the leading spaces from the string.
Example:
string = " javatpoint "
string2 = " javatpoint "
print(string)
print(string2)
print("After stripping all leading whitespaces:")
print(string.lstrip())
print(string2.lstrip())
Output:
javatpoint
javatpoint
After stripping all leading whitespaces:
javatpoint
javatpoint