Sometimes, a program needs to interact with the user’s to get some input data or information from the end user and process it to give the desired output. In Python, we have the input() function for taking the user input. The input() function prompts the user to enter data. It accepts all user input as string. The user may enter a number or a string but the input() function treats them as strings only.
The syntax for input() is:
input ([Prompt])
Prompt is the string we may like to display on the screen prior to taking the input, and it is optional. When a prompt is specified, first it is displayed on the screen after which the user can enter data. The input() takes exactly what is typed from the keyboard, converts it into a string and assigns it to the variable on left-hand side of the assignment operator (=). Entering data for the input function is terminated by pressing the enter key.
The variable fname will get the string ‘Arnab’, entered by the user. Similarly, the variable age will get the string ‘19’. We can typecast or change the datatype of the string data accepted from user to an appropriate numeric value. For example, the following statement will convert the accepted string to an integer. If the user enters any non-numeric value, an error will be generated.
Python uses the print() function to output data to standard output device — the screen. The function print() evaluates the expression before displaying it on the screen. The print() outputs a complete line and then moves to the next line for subsequent output.
The syntax for print() is:
print(value [, ..., sep = ' ', end = '\n'])
• sep: The optional parameter sep is a separator between the output values. We can use a character, integer or a string as a separator. The default separator is space.
• end: This is also optional and it allows us to specify any string to be appended after the last value. The default is a new line.
The third print function in the above example is concatenating strings, and we use + (plus) between two strings to concatenate them. The fourth print function also appears to be concatenating strings but uses commas (,) between strings. Actually, here we are passing multiple arguments, separated by commas to the print function. As arguments can be of different types, hence the print function accepts integer (16) along with strings here. But in case the print statement has values of different types and ‘+’ is used instead of comma, it will generate an error as discussed in the next section under explicit conversion.
