Functions and sample code of the if else statement in python
Introduction: if-else is used to determine what to do if one condition is met, or else what to do.
If-else statement syntax structure
If condition:
Code to be executed
Else:
Code to be executed
Condition: It is generally a relational expression or a bool value.
Execution Process: when the program runs at the if clause, it first determines the condition. if the condition is True, the return value is True, and the following code is executed. if the condition is not True, the return value is False, continue to execute the following code.
Example 1: Simulate User Logon
Prompt for username and password
If the user name is Admin and the password is 123.com, a message indicating successful logon is displayed.
If the user name is not Admin, the system prompts that the user does not exist.
If the password is not 123.com, a Password error is prompted.
Username = input ("enter username:") password = input ("Enter password:") if username. lower (). strip () = "admin" and password = "123.com": print (" Login successful! ") Else: print (" incorrect user name or password! ") # Lower () -- convert string to lowercase upper () -- convert string to uppercase # strip () -- remove spaces before and after string
Result:
C: \ python \ python.exe C:/python/demo/file2.py
Enter the User name: ADMIN
Enter the password 123.com
Login successful!
Process finished with exit code 0
Example 2:
Enter Mr. Wang (Chinese, English, and mathematics) score in the console application (out of 100 for a single subject)
Judgment:
1) if all the subjects pass, the prompt is: Congratulations, you have passed the test for all the subjects.
2) otherwise, you will be reminded that, unfortunately, you have not passed the exam and you need to make up the exam (no passing name)
Chinese = int (input ("Enter the chinese score:") maths = int (input ("Enter the math score :")) english = int (input ("Enter the english score:") get_course = "" if chinese >=60 and maths >=60 and english >=60: print ("congratulations, all subjects passed the test! ") Else: if chinese <= 60: get_course + =" chinese, "if maths <= 60: get_course + =" mathematics, "if english <= 60: get_course + = "English," print ("sorry, you did not pass the test. The retake subject is:" + get_course)
Result:
C: \ python \ python.exe C:/python/demo/file2.py
Enter the language score: 54
Enter the math score: 89
Enter English score: 32
Unfortunately, you did not pass the test. The subjects for retake exams are: Chinese, English,
Process finished with exit code 0
Example 3: (the first optimization of the small safflower case)
Enter Mr. Wang (Chinese, English, and mathematics) score in the console application (out of 100 for a single subject)
Judgment:
1) if one course is 100 points
2) if there are two doors greater than 90 points
3) if the number of the three doors is greater than 80
To meet the above conditions, reward a small red flower
Chinese = int (input ("Enter the chinese score:") maths = int (input ("Enter the math score :")) engist = int (input ("Enter the English score:") get_course = "" if (chinese = 100 or maths = 100 or engist = 100 ): if (chinese = 100): get_course + = "language," if (maths = 100): get_course + = "mathematics," if (englist = 100 ): get_course + = "English," print ("Your % s scored 100 points and rewarded a small red flower! "% Get_course) else: if (chinese> = 90 and maths> = 90) or (chinese> = 90 and englist> = 90) or (maths> = 90and englist> = 90): if (chinese> = 100): get_course + = "language," if (maths> = 90 ): get_course + = "mathematics," if (englist> = 90): get_course + = "English," print ("Your % s is greater than 90 points, reward a small red flower success! "% Get_course) else: if (chinese> = 80 and maths> = 80 and engist> = 80 ): print ("your three subjects are more than 80 points in Chinese, mathematics, and English, and you will be rewarded with a small safflower ")
Result:
C: \ python \ python.exe C:/python/demo/file2.py
Enter Chinese score: 86
Enter the math score: 98
Enter English score: 87
Your three subjects, including Chinese, mathematics, and English, all scored more than 80 points.
Summary
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