python first lesson

The two most basic python programs

1. Temperature conversion program

#TempConvert.py
TempStr = input("Please enter a temperature value with a sign: ")
if TempStr[-1] in ['F','f']:
    C = (eval (TempStr [0: -1]) - 32) /1.8
    print("The converted temperature is {:.2f}C".format(C))
elif TempStr[-1] in ['C','c']:
    F = 1.8 * eval (TempStr [0: -1]) + 32
    print("The converted temperature is: {:.2f}F".format(F))
else:
    print("Incorrect input format")

Computers are developed exponentially with reference to Moore's Law (integration doubles every two years, proposed by Intel Moore in 1965) (the only field in the world that has grown exponentially for more than 50 years, and Moore's Law will continue to grow in the foreseeable 30 years). remain in effect)

The c language was born in 1972 as the first widely used language

Python was born in 1990 and is one of the most popular and best used programming languages today (interpreted languages)

	birth time	language type	type of data	founder
c	1972	static language	Integers, floats, pointers, enums, etc.	DMRitchie (based on B language)
python	1990	scripting language	Integer, Float, String, List	Duido van Rossum

		example
static language	The compiler generates object code at a time, which is more fully optimized and runs faster	c,c++
scripting language	Program execution requires source code, maintenance is more flexible, and can cross operating systems	python,php,javascript

development path	2002	2008
python	python2.x	python3.x

Python is widely used, has powerful third-party libraries, advanced computing ecology, and is a super language. Computing ecology = standard library + third-party library

The evolution of computer technology

1946-1981 计算机系统结构第一台电脑

1981-2008 网络和视窗 Windows pc时代

2008-2016 08年Android系统出现进入复杂信息系统时代

16-今人工智能时代 16年alphago

import用法

1 import turtle 后面调用时比如这样turtle.penup()
2 from turtle import* 后面调用时，不用加turtle，直接加函数名，但缺点也很明显。
3 import turtle as bieming 可以起个小名，可以简化编程，例如import turtle as t

循环语句 range（） for 变量 in range()

for 变量 range (i): #意思是变量从0到i-1次

range() 产生循环计数数列

range(n) 产生0 到 n-1

range（m,n）产生m到 n-1的整数序列

循环语句 range（） for 变量 in range()

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