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>>> Enter marks: 55
             >>> Enter marks: 75
             >>> Enter marks: 85
             >>> Enter marks: 45
                 average marks: 65.0
            To sum up the above discussion of the for statement used in program 6.2, we give below its syntax:
              01 for control_variable in sequence:
              02       body of for loop
            In the above syntax description,
            • for is the keyword.
            • in is a keyword (membership operator).
            • sequence may be a list, string, tuple or dictionary.

            • control variable is a variable that takes the values in the sequence one by one.
            •  body of the loop may constitute a single statement or several statements, that will be executed for each value of the
              control variable in the sequence. Statements in the body of the loop are indented at the level of indentation next
              to the level at which the header:

                 for control_variable in sequence / values in range:
            appears. The first statement that appears at the same level as the header marks the end of the body of the for
            statement. However, a for statement may also be the last statement of a Python script. In such a case, the end of the
            Python script marks the end of the for statement.
            We can also describe the above syntax of the for statement in the form of a flowchart (see Fig 6.1):

                                                          For each item in
                                                             sequence


                                                      Last item   True
                                                      reached?


                                                          False


                                                    Statements
                                                                           Exit for loop


                                                         Fig 6.1: for loop

            6.3.1 Using String Sequences in a for Statement

            Suppose we wish to find the number of vowels in a string. For this purpose, let us write a program that accepts as input
            a string and returns the number of vowels in it.
              01 vowels = 'AEIOUaeiou'
              02 mystr = input('Enter a String: ')
              03 count = 0
              04 for char in mystr:
              05     if char in vowels:
              06         count += 1
              07 print('vowel count:',count)
            Sample Output:

             >>> Enter a String: Madras
                 vowel count: 2





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