How to read input and sum it using Python.
1. Read input
In Python, you can use the input() function to read user input. This function returns the user input as a string. For example, the following code reads a user-entered string and prints it:
input_str = input()
print(input_str)
When the user has finished inputting, they can press the Enter key to end the input. Note that the string returned by the input() function contains a carriage return character.
2. Convert string to number
After reading the input, we need to convert it into a number for calculation. You can use the int() function to convert a string to an integer, or the float() function to convert a string to a floating point number. For example, the following code reads an integer entered by the user and prints it:
input_str = input()
input_num = int(input_str)
print(input_num)
If the user input is a floating point number, you need to use the float() function for conversion. For example, the following code reads a user-entered floating point number and prints it out:
input_str = input()
input_num = float(input_str)
print(input_num)
- Sum
After reading the input and converting it to a number, we can sum the numbers. You can use a loop to read multiple numbers and a variable to hold the result of the sum. For example, the following code reads multiple integers and sums them:
sum = 0
while True:
input_str = input()
if input_str == "":
break
input_num = int(input_str)
sum += input_num
print(sum)
This code uses a while loop to read multiple integers and exit the loop when the user enters a blank line. In each loop, convert the read string into an integer and add it to the sum variable. Finally, the value of the sum variable is output.
If the user input is a floating point number, you need to use the float() function to convert it and set the initial value of the sum variable to 0.0. For example, the following code reads multiple floating point numbers and sums them:
sum = 0.0
while True:
input_str = input()
if input_str == "":
break
input_num = float(input_str)
sum += input_num
print(sum)
4. Summary
This article describes how to use Python to read input and sum it. First, use the input() function to read the string entered by the user and convert it to a number using the int() or float() function. Then, use a loop to read multiple numbers and use a variable to hold the result of the sum. Finally, the result of the summation is output.
Reading input and summing is a very basic operation in Python programming, and it is also an operation frequently used in daily development. By learning the methods introduced in this article, readers can further master the basic syntax of Python and improve their programming abilities.
Java language required
- Read input
In Java, you can use the Scanner class to read user input. This class provides multiple methods to read different types of data. For example, nextInt() can read integers, nextFloat() can read floating point numbers, nextLine() can read a line of strings, etc. The following code reads a user-entered string and prints it out:
Scanner scanner = new Scanner(System.in);
String inputStr = scanner.nextLine();
System.out.println(inputStr);
When the user has finished inputting, they can press the Enter key to end the input. Note that the string returned by the nextLine() method contains a carriage return character.
2. Convert string to number
After reading the input, we need to convert it into a number for calculation. You can use the Integer.parseInt() method to convert a string to an integer, or the Float.parseFloat() method to convert a string to a floating point number. For example, the following code reads an integer entered by the user and prints it:
Scanner scanner = new Scanner(System.in);
String inputStr = scanner.nextLine();
int inputNum = Integer.parseInt(inputStr);
System.out.println(inputNum);
If the user input is a floating point number, you need to use the Float.parseFloat() method to convert it. For example, the following code reads a user-entered floating point number and prints it out:
Scanner scanner = new Scanner(System.in);
String inputStr = scanner.nextLine();
float inputNum = Float.parseFloat(inputStr);
System.out.println(inputNum);
- Sum
After reading the input and converting it to a number, we can sum the numbers. You can use a loop to read multiple numbers and a variable to hold the result of the sum. For example, the following code reads multiple integers and sums them:
Scanner scanner = new Scanner(System.in);
int sum = 0;
while (scanner.hasNext()) {
String inputStr = scanner.nextLine();
if (inputStr.equals("")) {
break;
}
int inputNum = Integer.parseInt(inputStr);
sum += inputNum;
}
System.out.println(sum);
This code uses a while loop to read multiple integers and exit the loop when the user enters a blank line. In each loop, convert the read string into an integer and add it to the sum variable. Finally, the value of the sum variable is output.
If the user input is a floating point number, you need to use the Float.parseFloat() method to convert it and set the initial value of the sum variable to 0.0. For example, the following code reads multiple floating point numbers and sums them:
Scanner scanner = new Scanner(System.in);
float sum = 0.0f;
while (scanner.hasNext()) {
String inputStr = scanner.nextLine();
if (inputStr.equals("")) {
break;
}
float inputNum = Float.parseFloat(inputStr);
sum += inputNum;
}
System.out.println(sum);
4. Summary
This article describes how to use Java to read input and sum it. First, use the Scanner class to read the string entered by the user and convert it to a number using the Integer.parseInt() or Float.parseFloat() method. Then, use a loop to read multiple numbers and use a variable to hold the result of the sum. Finally, the result of the summation is output.
Reading input and summing is a very basic operation in Java programming, and it is also an operation frequently used in daily development. By learning the methods introduced in this article, readers can further master the basic syntax of Java and improve their programming abilities.