Python for 循环语句：遍历任何序列的项目，可以是字符串、列表、元组、字典、集合对象。
流程图：
第一种：
''' for 迭代对象 in 序列: 代码块(一行语句或多行代码) '''
第二种：
''' for 迭代对象 in 序列: 代码块(一行语句或多行代码) else: 代码块(一行语句或多行代码) '''
示例：
第一种：
for i in range(4): print(i) # 0 # 1 # 2 # 3
# 字符串 strs = "Hello World." for i in strs: print(i,end=" ") # H e l l o W o r l d . print() # 列表 lst = [1,2.3,8+9j,'abc',(4,5),{7,8,'a'},{'a':4}] for i in lst: print(i,end=" ") # 1 2.3 (8+9j) abc (4, 5) {8, 'a', 7} {'a': 4} print() # 元组 tup = (1,2,3,4,5,6) for i in tup: print(i,end=" ") # 1 2 3 4 5 6 print() # 字典 dic = {'a':{'b':123},(4,5):'str',123:[4,5,6]} # 键为不可变类型 字符串、元组、数字 for i in dic: print(i,end=" ") # a (4, 5) 123 print() # 集合 set_1 = {1,2.5,'a',(7,8,9)} for i in set_1: print(i,end=" ") # 1 2.5 a (7, 8, 9) print()
第二种：
for i in range(4): print(i) else: print("运行OK") # 0 # 1 # 2 # 3 # 运行OK
# 字符串 strs = "Hello World." for i in strs: print(i,end=" ") # H e l l o W o r l d . 运行OK else: print("运行OK") print() # 列表 lst = [1,2.3,8+9j,'abc',(4,5),{7,8,'a'},{'a':4}] for i in lst: print(i,end=" ") # 1 2.3 (8+9j) abc (4, 5) {8, 'a', 7} {'a': 4} 运行OK else: print("运行OK") print() # 元组 tup = (1,2,3,4,5,6) for i in tup: print(i,end=" ") # 1 2 3 4 5 6 运行OK else: print("运行OK") print() # 字典 dic = {'a':{'b':123},(4,5):'str',123:[4,5,6]} # 键为不可变类型 字符串、元组、数字 for i in dic: print(i,end=" ") # a (4, 5) 123 运行OK else: print("运行OK") print() # 集合 set_1 = {1,2.5,'a',(7,8,9)} for i in set_1: print(i,end=" ") # 1 2.5 a (7, 8, 9) 运行OK else: print("运行OK") print()
2020-02-06