if if_stmt ::= "if" assignment_expression ":" suite ("elif" assignment_expression ":" suite)* ["else" ":" suite] 用法： if EXPRESSION1: SUITE1elif EXPRESSION2: SUITE2else: SUITE 常用的操作符： "<"：小于 "<="：小于等于 ">"：大于 ">="：大于等于 "=="：等于 "!="：不等于 "and"：并且 "or"：或者 with with_stmt ::= "with" ( "(" with_stmt_contents ","? ")" | with_stmt_contents ) ":" suitewith_stmt_contents ::= with_item ("," with_item)*with_item ::= expression ["as" target] 用法： with EXPRESSION as TARGET: SUITE或者with A() as a, B() as b: SUITE或者with A() as a: with B() as b: SUITE或者with ( A() as a, B() as b,): SUITE match（3.10新特性） match_stmt ::= 'match' subject_expr ":" NEWLINE INDENT case_block+ DEDENTsubject_expr ::= star_named_expression "," star_named_e...

列表排序方法 sort()：仅对list对象进行排序，会改变list自身的顺序，没有返回值，即原地排序 sorted()：对所有可迭代对象进行排序，返回排序后的新对象，原对象保持不变； sort() list.sort(key=None, reverse=False) key：设置排序方法，或指定list中用于排序的元素； reverse：升降序排列，默认为升序排列； 例子： nums = [2, 3, 5, 1, 6]nums.sort()print(nums) # [1, 2, 3, 5, 6]nums.sort(key=None, reverse=True)print(nums) # [6, 5, 3, 2, 1] students = [('john', 'C', 15), ('jane', 'A', 12), ('dave', 'B', 10)]students.sort(key=lambda x: x[2]) # 按照列表中第三个元素排序print(students) # [('dave', 'B', 10), ('jane', 'A', 12), ('john', 'C', 15)] sorted() sorted(iterable [, key[, reverse]]) key ：设置排序方法，或指定迭代对象中，用于排序的元素； reverse ：升降序排列，默认为升序排列； 例子： nums = [2, 3, 5, 1, 6]newNums = sorted(nums)print(nums) # [2, 3, 5, 1, 6]print(newNums) # [1, 2, 3, 5, 6]students = [('john', 'C', 15), ('jane', 'A', 12), ('dave', 'B', 10)]newStude...

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