for循环

"""语法：
for item in 某个数据类型: 字符串、列表、元组、字典、集合等
    代码块
循环次数由元素个数决定"""
# s = "hello"
# list_1 = [1, 2, 3]
# dic_1 = {"age": "18", "name": "star"}
# for item in s:  # 遍历s里面的元素，然后赋值给item
#     print(item)
#     print("&&44")
# for i in list_1:
#     print(i)
# for i in dic_1:  # 字典返回key
#     print(i)
# for i in dic_1:  # 字典返回value
#     print(dic_1[i])
# for i in dic_1.items():  # .items()返回键值队
#     print(i)
#
# for i in dic_1.keys():  # .keys()返回键
#     print(i)
#
# for i in dic_1.keys():  # .keys()返回键
#     print(i)

# for k, v in dic_1.items():  # 可以单独取出键值对的值
#     print(k, v)
#
# """例题：利用for循环，完成列表里所有数字相加"""
# list_2 = [1, 4, 5, 8, 3]
# s = 0
# for i in list_2:
#     s += i
# print("所有值的和是{}".format(s))

"""range函数 range(m,n,k),m头，n尾，k步长，步长默认1，取头不取尾
用来生成整数序列，不是随机数
生成的结果不是列表，可以转成列表"""
# print(list(range(1, 6, 2)))
# print(list(range(4)))  # 头默认为0

"""例题,打印列表的每个元素值"""
# list_3 = [1, 4, 6, 5, 7]
# for i in range(5):
#     print(list_3[i])

"""利用for循环和range函数 完成1-100 的整数求和，包含1、100"""
# s = 0
# for i in range(1, 101):
#     s += i
# print(s)

"""嵌套循环 单独打印列表的某个元素"""
# L = [["star", "moon", "son"], ["yes", "no", "equal"]]
# for i in L:  #  每次循环拿到一个子列表
#     for s in i:  #  每次循环拿到子列表的元素
#         print(s)

"""
输出直角三角形
*
**
***
****
*****
"""
for i in range(1, 6):
    print("*" * i)