Page 259 - Ai_V1.0_Class9
P. 259
• index(): It returns the index number of the value given in the function. For example,
city=["Delhi", "Mumbai", "Kolkata", "Chennai"]
print (city.index("Kolkata"))
Output: 2
print (city.index("Pune"))
Output: ValueError: 'Pune' is not in list
It returns ValueError exception if the value is not found in the list.
• count(): This function counts the number of occurrences of the specified value in the given list. If the value
doesn't exist, then the function returns 0. For example,
marks = [56, 67, 45, 78, 56, 78, 12]
marks.count(78)
Output: 2
marks.count(10) # 10 does not exist in the list.
Output: 0
At a Glance
• A program is written in any programming language which the computer can understand and execute.
• An algorithm is a step-by-step approach to identify and solve a problem in a finite time.
• A flowchart is a graphical representation of an algorithm.
• Keywords in Python are predefined and reserved words with special meanings and purposes.
• Identifiers are the user defined names of variables, list, dictionary, tuples, classes, etc.
• Variable is a name given to a memory location to hold a specific value.
• Data types specify the kind of a value a variable can store. It helps us to identify the kind of operation that can be
performed on that specific data type.
• Operators are special symbols used to perform mathematical, logical and relational operations on variables and values.
• Comments are used to increase the readability of the code.
• The print() function is used to print an output on the screen.
• A step-by-step process of execution of code is called sequential flow of control.
• Selection flow of control is achieved through conditional statements.
• The range( ) function is an inbuilt function that is used to generate a sequence of values between the specified range.
• The elements of a list can be accessed by using its index number starts with 0 (zero).
Introduction to Python 257

