Python程序计算列表中的正数和负数

给定一个数字列表，编写一个Python程序来计算列表中的正数和负数。

例子：

Input: list1 = [2, -7, 5, -64, -14]
Output: pos = 2, neg = 3

Input: list2 = [-12, 14, 95, 3]
Output: pos = 3, neg = 1

示例 #1：使用 for 循环计算给定列表中的正数和负数

使用 for 循环迭代列表中的每个元素并检查是否 num >= 0，即检查正数的条件。如果条件满足，则增加 pos_count 否则增加 neg_count。

# Python program to count positive and negative numbers in a List
  
# list of numbers
list1 = [10, -21, 4, -45, 66, -93, 1]
  
pos_count, neg_count = 0, 0
  
# iterating each number in list
for num in list1:
      
    # checking condition
    if num >= 0:
        pos_count += 1
  
    else:
        neg_count += 1
          
print("Positive numbers in the list: ", pos_count)
print("Negative numbers in the list: ", neg_count)

输出：

Positive numbers in the list:  4
Negative numbers in the list:  3

示例 #2：使用 while 循环

# Python program to count positive and negative numbers in a List
  
# list of numbers
list1 = [-10, -21, -4, -45, -66, 93, 11]
  
pos_count, neg_count = 0, 0
num = 0
  
# using while loop     
while(num < len(list1)):
      
    # checking condition
    if list1[num] >= 0:
        pos_count += 1
    else:
        neg_count += 1
      
    # increment num 
    num += 1
      
print("Positive numbers in the list: ", pos_count)
print("Negative numbers in the list: ", neg_count)

输出：

Positive numbers in the list:  2
Negative numbers in the list:  5

示例 #3：使用Python Lambda 表达式

# Python program to count positive
# and negative numbers in a List
  
# list of numbers
list1 = [10, -21, -4, 45, 66, 93, -11]
  
neg_count = len(list(filter(lambda x: (x < 0), list1)))
  
# we can also do len(list1) - neg_count
pos_count = len(list(filter(lambda x: (x >= 0), list1)))
  
print("Positive numbers in the list: ", pos_count)
print("Negative numbers in the list: ", neg_count)

输出：

Positive numbers in the list:  4
Negative numbers in the list:  3

示例 #4：使用列表理解

# Python program to count positive
# and negative numbers in a List
  
# list of numbers
list1 = [-10, -21, -4, -45, -66, -93, 11]
  
only_pos = [num for num in list1 if num >= 1]
pos_count = len(only_pos)
  
print("Positive numbers in the list: ", pos_count)
print("Negative numbers in the list: ", len(list1) - pos_count)

输出：

Positive numbers in the list:  1
Negative numbers in the list:  6