elif python

Python Elif关键字 (Python elif keyword)

elif is a keyword (case-sensitive) in python, it is used in the conditional statement, if we have multiple conditions to be checked, we have to use elif keyword to check next condition.

elif是python中的一个关键字(区分大小写)，在条件语句中使用，如果我们要检查多个条件，则必须使用elif关键字检查下一个条件。

Note: First condition is checked with if keyword and other all are checked with elif keyword and if the last/default block (if any condition is not true) is written with else keyword.

注意：第一个条件用if关键字检查，其他全部用elif关键字检查，最后/默认块(如果任何条件不成立)是否用else关键字写。

Syntax of elif keyword

elif关键字的语法

    if test_condition1:
statement(s)-true-1
elif test_condition2:
statement(s)-true-2
.
.
..
else:
statement(s)-false

Here, if test_condition1 is True, then statement(s)-true-1 will be executed, if the test_condition2 is True, then statement(s)-true-2 will be executed, and so on... we can test multiple conditions, if all conditions are not True, then else block (statement(s)-false) will be executed.

在这里，如果test_condition1为True ，则将执行语句-true-1 ，如果test_condition2为True ，则将执行语句-true-2 ，依此类推...我们可以测试多个条件，如果所有条件都不都是True ，那么将执行else块( statement-s false )。

Example:

例：

    Input:
num = -21
# condition
if num>0:
print(num," is a positive value")
elif num<0:
print(num," is a negative value")
else:
print(num," is a zero")
Output:
-21  is a negative value

if，else，elif关键字的Python示例 (Python examples of if, else, elif keywords)

Example 1: Input a number and check whether it is positive, negative or zero.

示例1：输入一个数字并检查它是正数，负数还是零。

# python code to demonstrate example of 
# if, else and elif keywords 
# Input a number and check whether 
# it is positive, negative or zero.
# input
num = int(input("Enter a number: "))
# conditions
if num>0:
print(num," is a positive value")
elif num<0:
print(num," is a negative value")
else:
print(num," is a zero")

Output

输出量

First run:
Enter a number: -21
-21  is a negative value
Second run:
Enter a number: 2
2  is a positive value
Third run:
Enter a number: 0
0  is a zero

Example 2: Input three numbers and find largest number.

示例2：输入三个数字并找到最大的数字。

# python code to demonstrate example of 
# if, else and elif keywords 
# Input three numbers and find largest number.
a = int(input("Enter first number :"))
b = int(input("Enter second number:"))
c = int(input("Enter third number :"))
large =0
# conditions
if a>b and a<c:
large = a;
elif b>a and b>c:
large = b;
else:
large = c;
# printing largest number 
print("largest number is: ", large)

Output

输出量

Enter first number :10
Enter second number:30
Enter third number :20
largest number is:  30

翻译自: https://www.includehelp.com/python/elif-keyword-with-example.aspx

elif python