Python语言进阶
重要知识点
生成式（推导式）的用法
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12prices = {
'AAPL': 191.88,
'GOOG': 1186.96,
'IBM': 149.24,
'ORCL': 48.44,
'ACN': 166.89,
'FB': 208.09,
'SYMC': 21.29
}
# 用股票价格大于100元的股票构造一个新的字典
prices2 = {key: value for key, value in prices.items() if value > 100}
print(prices2)说明：生成式（推导式）可以用来生成列表、集合和字典。
嵌套的列表的坑
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10names = ['关羽', '张飞', '赵云', '马超', '黄忠']
courses = ['语文', '数学', '英语']
# 录入五个学生三门课程的成绩
# 错误 - 参考http://pythontutor.com/visualize.html#mode=edit
# scores = [[None] * len(courses)] * len(names)
scores = [[None] * len(courses) for _ in range(len(names))]
for row, name in enumerate(names):
for col, course in enumerate(courses):
scores[row][col] = float(input(f'请输入{name}的{course}成绩: '))
print(scores)Python Tutor - VISUALIZE CODE AND GET LIVE HELP
