📜  Python中的嵌套if语句

📅  最后修改于: 2022-05-13 01:55:50.395000             🧑  作者: Mango

Python中的嵌套if语句

现实生活中会出现一些情况,当我们需要做出一些决定时,我们会根据这些决定决定下一步应该做什么。在编程中也会出现类似的情况,我们需要做出一些决定,并基于这些决定,我们将执行下一个代码块。这是在Python中的决策语句的帮助下完成的。

例子:

# Python program to demonstrate
# decision making
  
i = 20; 
if (i < 15): 
    print ("i is smaller than 15") 
    print ("i'm in if Block") 
else: 
    print ("i is greater than 15") 
    print ("i'm in else Block") 
print ("i'm not in if and not in else Block") 

输出:

i is greater than 15
i'm in else Block
i'm not in if and not in else Block

嵌套 if 语句

我们可以在另一个 if...elif...else 语句中包含一个 if...elif...else 语句。这在计算机编程中称为嵌套。任意数量的这些语句都可以相互嵌套。缩进是确定嵌套级别的唯一方法。这可能会让人感到困惑,所以如果可以的话,必须避免它。

句法:

if (condition1):
   # Executes when condition1 is true
   if (condition2): 
      # Executes when condition2 is true
   # if Block is end here
# if Block is end here

流程图

嵌套if1

示例 1:

# Python program to demonstrate
# nested if statement
  
   
num = 15
if num >= 0:
    if num == 0:
        print("Zero")
    else:
        print("Positive number")
else:
    print("Negative number")

输出:

Positive number

示例 2:

# Python program to demonstrate
# nested if statement
  
  
i = 13
  
if (i == 13): 
    #  First if statement 
    if (i < 15): 
        print ("i is smaller than 15") 
          
    # Nested - if statement 
    # Will only be executed if statement above 
    # it is true 
    if (i < 12): 
        print ("i is smaller than 12 too") 
    else: 
        print ("i is greater than 12 and smaller than 15")

输出:

i is smaller than 15
i is greater than 12 and smaller than 15