本文目录导读：
我来为你介绍Python中使用for循环遍历各种数据类型的经典案例。
遍历列表(list)
# 基础遍历
fruits = ['苹果', '香蕉', '橙子', '葡萄']
for fruit in fruits:
print(fruit)
# 带索引遍历
for index, fruit in enumerate(fruits):
print(f"第{index+1}个水果是：{fruit}")
# 使用range遍历索引
for i in range(len(fruits)):
print(fruits[i])
遍历字典(dict)
# 学生成绩示例
scores = {'张三': 95, '李四': 88, '王五': 92}
# 遍历键
for name in scores:
print(f"学生：{name}")
# 遍历键值对
for name, score in scores.items():
print(f"{name}的分数是：{score}")
# 只遍历值
for score in scores.values():
print(f"分数：{score}")
遍历字符串
text = "Hello Python"
# 逐字符遍历
for char in text:
print(char, end=' ')
# 带索引遍历
for i, char in enumerate(text):
print(f"位置{i}的字符：{char}")
遍历元组(tuple)
# 坐标点示例
points = (10, 20, 30, 40, 50)
for point in points:
print(f"坐标值：{point}")
# 解包元组列表
coordinates = [(1, 2), (3, 4), (5, 6)]
for x, y in coordinates:
print(f"x={x}, y={y}")
遍历集合(set)
# 去重后的数字集合
numbers = {1, 2, 3, 2, 1, 4, 5}
print("集合中的元素：")
for num in numbers:
print(num)
# 注意：集合是无序的，遍历顺序可能不确定
多层循环遍历
# 二维列表遍历
matrix = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
]
for row in matrix:
for element in row:
print(element, end=' ')
print() # 换行
# 乘法表
for i in range(1, 10):
for j in range(1, i+1):
print(f"{j}x{i}={i*j}", end='\t')
print()
实用案例：数据处理
# 学生成绩处理
students = [
{'name': '张三', 'scores': [85, 92, 78]},
{'name': '李四', 'scores': [90, 88, 95]},
{'name': '王五', 'scores': [70, 85, 80]}
]
print("学生成绩统计：")
for student in students:
name = student['name']
scores = student['scores']
total = sum(scores)
avg = sum(scores) / len(scores)
print(f"{name}: 总分={total}, 平均分={avg:.1f}")
带条件的遍历
# 过滤偶数
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
print("偶数列表：")
even_numbers = [num for num in numbers if num % 2 == 0]
print(even_numbers)
# break和continue示例
for num in range(1, 20):
if num == 10:
break # 遇到10停止
if num % 3 == 0:
continue # 跳过3的倍数
print(num, end=' ')
遍历文件内容
# 读取文件（假设有data.txt文件）
try:
with open('data.txt', 'r', encoding='utf-8') as file:
for line_number, line in enumerate(file, 1):
print(f"第{line_number}行：{line.strip()}")
except FileNotFoundError:
print("文件不存在")
实用技巧：zip并行遍历
# 并行遍历多个列表
names = ['张三', '李四', '王五']
ages = [25, 30, 28]
cities = ['北京', '上海', '深圳']
for name, age, city in zip(names, ages, cities):
print(f"{name}，{age}岁，来自{city}")
这些案例涵盖了Python中最常见的遍历场景，实际开发中，根据不同的数据结构选择合适的遍历方式可以提高代码效率，记住使用enumerate()获取索引，items()遍历字典，以及zip()并行遍历多个序列都是很实用的技巧。
