Python学习笔记Day1
input 输入
示例1
password = input("请输入密码")
print("密码是:",password)
示例2
input的输入类型是字符型,可以用type函数打印类型。print输出 字符和整型 的用法如下
a = input("输入:") #字符类型
print(type(a))
print("你输入了一个数字:%s"%a)
if语句
示例1
if False:
print("True")
else:
print("False")
print("DEMO END")
示例2
score = 98
if score >= 90 and score <= 100:
print("优秀")
elif score < 90 and score >60:
print("等级B")
elif score < 60:
print("不及格")
示例3
导入生成随机数的库,石头剪刀布游戏
import random
system_out = random.randint(0,2)
your_out = int(input("你打算出什么:"))
print("系统随机数字为%d"%system_out)
if your_out >= 3:
print("请规范输入:剪刀(0)、石头(1)、布(2)")
if your_out > system_out:
print("you win")
elif your_out == system_out:
print("equal")
else:
print("you lost")
for语句
示例1
for i in range(5):
print(i)
示例2
最后一个参数为步长,从1开始,13并不打印
for i in range(1,13,3):
print(i)
示例3
name = "fine"
for x in name:
print(x,end="\t")
示例4
a = ["aa","bb","cc"]
for i in range(len(a)):
print(i,a[i])
while语句
示例1
i = 0;
while i < 5:
print("i=%d"%i)
i += 1
示例2
100之内累加
sum = 0
for i in range(0,101):
sum = sum + i
print(sum)
示例3
九九乘法表
i = 1
while i < 10:
for j in range(1,10):
print("%d*%d=%d"%(i,j,i*j),end="\t")
if i == j:
i += 1
print()
break
String
示例1
注意转义字符的应用
word = 'I\'m a student' #转义
sentence = "This is a sentence"
paragraph = \"""
这是一个段落
可以由多行组成
\"""
print(word)
示例2
str = "chengdu"
print(str)
print(str[0:5])
print(str[0:5:2]) #[起始位置:结束位置:步长]
print(str + "你好")
print(str*3)
print("hello\npython")
print(r"hello\npython")#消除\n作用