Explanation of real use of Args for a function.

Author: sanjaypradeep

ArgsKwArgs/args.py

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+
+
+# Suppose, we define a function for addition of 3 numbers.
+
+#Example 1: Function to add 3 numbers
+def adder(x,y,z):
+    print("sum:",x+y+z)
+
+adder(10,12,13) #sum: 35
+# When we run the above program, the output will be
+
+
+# In above program we have adder() function with three arguments x, y and z. When we pass three values while calling adder() function, we get sum of the 3 numbers as the output.
+
+# Lets see what happens when we pass more than 3 arguments in the adder() function.
+
+def adder(x,y,z):
+    print("sum:",x+y+z)
+
+adder(5,10,15,20,25) #TypeError: adder() takes 3 positional arguments but 5 were given
+# When we run the above program, the output will be
+
+# In the above program, we passed 5 arguments to the adder() function instead of 3 arguments due to which we got TypeError.
+
+# Introduction to *args and **kwargs in Python
+# In Python, we can pass a variable number of arguments to a function using special symbols. There are two special symbols:
+
+'''
+*args (Non Keyword Arguments)
+**kwargs (Keyword Arguments)
+We use *args and **kwargs as an argument when we are unsure about the number of arguments to pass in the functions.
+
+Python *args
+As in the above example we are not sure about the number of arguments that can be passed to a function. Python has *args which allow us to pass the variable number of non keyword arguments to function.
+
+In the function, we should use an asterisk * before the parameter name to pass variable length arguments.The arguments are passed as a tuple and these passed arguments make tuple inside the function with same name as the parameter excluding asterisk *.
+'''
+
+# Example 2: Using *args to pass the variable length arguments to the function
+
+def adder(*num):
+    sum = 0
+    
+    for n in num:
+        sum = sum + n
+
+    print("Sum:",sum)
+
+adder(3,5) #Sum: 8
+adder(4,5,6,7) # Sum: 22
+adder(1,2,3,5,6) # Sum: 17
+
+
+# In the above program, we used *num as a parameter which allows us to pass variable length argument list to the adder() function. 
+# Inside the function, we have a loop which adds the passed argument and prints the result. 
+# We passed 3 different tuples with variable length as an argument to the function.
+
+# Python **kwargs
+# Python passes variable length non keyword argument to function using *args but we cannot use this to pass keyword argument. For this problem Python has got a solution called **kwargs, it allows us to pass the variable length of keyword arguments to the function.
+
+# In the function, we use the double asterisk ** before the parameter name to denote this type of argument. The arguments are passed as a dictionary and these arguments make a dictionary inside function with name same as the parameter excluding double asterisk **.
+