Python 代码片段 |文档
python 课程代码示例
这是我使用和创建的 python 代码的文档,用于学习 python。
它易于理解和学习。欢迎从这里学习。
我很快就会用更多高级主题更新博客。
目录
- 第一个节目
- 变量和数据类型
- 字符串
- 数字
- 获取用户的输入
- 构建一个基本计算器
- 第一个 madlibs
- 列表
- 列出函数
- 元组
- 功能
- 退货声明
- if 语句
- 如果比较
- 猜谜游戏2
- for 循环
- 指数函数
- 二维列表和 for 循环
第一个节目
此程序用于展示 print() 命令如何工作。
# this is a simple "hello world" program that demonstrates basic print statements# print the string "hello world" to the consoleprint("hello world")# print the integer 1 to the consoleprint(1)# print the integer 20 to the consoleprint(20)
变量和数据类型
python 中的变量是用于存储值的保留内存位置。
数据类型定义变量可以保存的数据类型,即整数、浮点、字符串等
# this program demonstrates the use of variables and string concatenation# assign the string "dipsan" to the variable _name_name = "dipsan"# assign the integer 20 to the variable _age_age = 20# assign the string "piano" to the variable _instrument_instrument = "piano"# print a sentence using string concatenation with the _name variableprint("my name is" + _name + ".")# print a sentence using string concatenation, converting _age to a stringprint("i'm" + str(_age) + "years old") # converting int to string for concatenation# print a simple stringprint("i dont like hanging out")# print a sentence using string concatenation with the _instrument variableprint("i love " + _instrument + ".")
弦乐
用于存储和操作文本的字符序列。它们是通过将文本括在单引号 ('hello')、双引号 ("hello") 或多行字符串的三引号 ('''hello''') 中来创建的。示例:“你好,世界!”。
# this script demonstrates various string operations# assign a string to the variable 'phrase'phrase = "dipsansacademy"# print a simple stringprint("this is a string")# concatenate strings and print the resultprint('this' + phrase + "")# convert the phrase to uppercase and printprint(phrase.upper())# convert the phrase to lowercase and printprint(phrase.lower())# check if the uppercase version of phrase is all uppercase and print the resultprint(phrase.upper().isupper())# print the length of the phraseprint(len(phrase))# print the first character of the phrase (index 0)print(phrase[0])# print the second character of the phrase (index 1)print(phrase[1])# print the fifth character of the phrase (index 4)print(phrase[4])# find and print the index of 'a' in the phraseprint(phrase.index("a"))# replace "dipsans" with "kadariya" in the phrase and print the resultprint(phrase.replace("dipsans", "kadariya"))
数字
数字用于各种数字运算和数学函数:
# import all functions from the math modulefrom math import * # importing math module for additional math functions# this script demonstrates various numeric operations and math functions# print the integer 20print(20)# multiply 20 by 4 and print the resultprint(20 * 4)# add 20 and 4 and print the resultprint(20 + 4)# subtract 4 from 20 and print the resultprint(20 - 4)# perform a more complex calculation and print the resultprint(3 + (4 - 5))# calculate the remainder of 10 divided by 3 and print the resultprint(10 % 3)# assign the value 100 to the variable _num_num = 100# print the value of _numprint(_num)# convert _num to a string, concatenate with other strings, and printprint(str(_num) + " is my fav number") # converting int to string for concatenation# assign -10 to the variable new_numnew_num = -10# print the absolute value of new_numprint(abs(new_num)) # absolute value# calculate 3 to the power of 2 and print the resultprint(pow(3, 2)) # power function# find the maximum of 2 and 3 and print the resultprint(max(2, 3)) # maximum# find the minimum of 2 and 3 and print the resultprint(min(2, 3)) # minimum# round 3.2 to the nearest integer and print the resultprint(round(3.2)) # rounding# round 3.7 to the nearest integer and print the resultprint(round(3.7))# calculate the floor of 3.7 and print the resultprint(floor(3.7)) # floor function# calculate the ceiling of 3.7 and print the resultprint(ceil(3.7)) # ceiling function# calculate the square root of 36 and print the resultprint(sqrt(36)) # square root
获取用户的输入
此程序用于演示如何使用 input() 函数获取用户输入:
# this script demonstrates how to get user input and use it in string concatenation# prompt the user to enter their name and store it in the 'name' variablename = input("enter your name : ")# prompt the user to enter their age and store it in the 'age' variableage = input("enter your age. : ")# print a greeting using the user's input, concatenating stringsprint("hello " + name + " youre age is " + age + " .")
构建一个基本计算器
该程序创建一个简单的计算器,将两个数字相加:
# this script creates a basic calculator that adds two numbers# prompt the user to enter the first number and store it in 'num1'num1 = input("enter first number : ")# prompt the user to enter the second number and store it in 'num2'num2 = input("enter second number: ")# convert the input strings to integers and add them, storing the resultresult = int(num1) + int(num2)# print the result of the additionprint(result)
第一疯狂
这个程序创建了一个简单的 mad libs 游戏:
# this program is used to create a simple mad libs game.# prompt the user to enter an adjective and store it in 'adjective1'adjective1 = input("enter an adjective: ")# prompt the user to enter an animal and store it in 'animal'animal = input("enter an animal: ")# prompt the user to enter a verb and store it in 'verb'verb = input("enter a verb: ")# prompt the user to enter another adjective and store it in 'adjective2'adjective2 = input("enter another adjective: ")# print the first sentence of the mad libs story using string concatenationprint("i have a " + adjective1 + " " + animal + ".")# print the second sentence of the mad libs storyprint("it likes to " + verb + " all day.")# print the third sentence of the mad libs storyprint("my " + animal + " is so " + adjective2 + ".")
列表
列表是python中有序且可更改的项目的集合。列表中的每个项目(或元素)都有一个索引,从 0 开始。列表可以包含不同数据类型的项目(如整数、字符串,甚至其他列表)。
列表使用方括号 [] 定义,每个项目用逗号分隔。
# this script demonstrates basic list operations# create a list of friends' namesfriends = ["roi", "alex", "jimmy", "joseph"]# print the entire listprint(friends)# print the first element of the list (index 0)print(friends[0])# print the second element of the list (index 1)print(friends[1])# print the third element of the list (index 2)print(friends[2])# print the fourth element of the list (index 3)print(friends[3])# print the last element of the list using negative indexingprint(friends[-1])# print a slice of the list from the second element to the endprint(friends[1:])# print a slice of the list from the second element to the third (exclusive)print(friends[1:3])# change the second element of the list to "kim"friends[1] = "kim"# print the modified listprint(friends)
列表功能
此脚本展示了各种列表方法:
# this script demonstrates various list functions and methods# create a list of numbersnumbers = [4, 6, 88, 3, 0, 34]# create a list of friends' namesfriends = ["roi", "alex", "jimmy", "joseph", "kevin", "tony", "jimmy"]# print both listsprint(numbers)print(friends)# add all elements from 'numbers' to the end of 'friends'friends.extend(numbers)# add "hulk" to the end of the 'friends' listfriends.append("hulk")# insert "mikey" at index 1 in the 'friends' listfriends.insert(1, "mikey")# remove the first occurrence of "roi" from the 'friends' listfriends.remove("roi")# print the index of "mikey" in the 'friends' listprint(friends.index("mikey"))# remove and print the last item in the 'friends' listprint(friends.pop())# print the current state of the 'friends' listprint(friends)# remove all elements from the 'friends' listfriends.clear()# print the empty 'friends' listprint(friends)# sort the 'numbers' list in ascending ordernumbers.sort()# print the sorted 'numbers' listprint(numbers)
元组
元组是python中有序但不可更改(不可变)的项目的集合。一旦创建了元组,就无法添加、删除或更改其元素。与列表一样,元组可以包含不同数据类型的项目。
元组使用括号 () 定义,每个项目用逗号分隔。
# this script introduces tuples and their immutability# create a tuple with two elementsvalues = (3, 4)# print the entire tupleprint(values)# print the second element of the tuple (index 1)print(values[1])# the following line would cause an indexerror if uncommented:# print(values[2]) # this would cause an indexerror# the following line would cause a typeerror if uncommented:# values[1] = 30 # this would cause a typeerror as tuples are immutable# the following line would print the modified tuple if the previous line worked:# print(values)
功能
函数是执行特定任务的可重用代码块。函数可以接受输入(称为参数)、处理它们并返回输出。函数有助于组织代码,使其更加模块化,并避免重复。
在 python 中,函数是使用 def 关键字定义的,后跟函数名、括号 () 和冒号 :。函数内的代码是缩进的。
此代码演示了如何定义和调用函数:
# this script demonstrates how to define and call functions# define a function called 'greetings' that prints two linesdef greetings(): print("hi, welcome to programming world of python") print("keep learning")# print a statement before calling the functionprint("this is first statement")# call the 'greetings' functiongreetings()# print a statement after calling the functionprint("this is last statement")# define a function 'add' that takes two parameters and prints their sumdef add(num1, num2): print(int(num1) + int(num2))# call the 'add' function with arguments 3 and 4add(3, 4)
退货声明
return 语句在函数中用于向调用者发送回(或“返回”)一个值。当执行return时,函数结束,return后指定的值被发送回函数调用的地方。
此程序展示了如何在函数中使用 return 语句:
# this script demonstrates the use of return statements in functions# define a function 'square' that returns the square of a numberdef square(num): return num * num # any code after the return statement won't execute# call the 'square' function with argument 2 and print the resultprint(square(2))# call the 'square' function with argument 4 and print the resultprint(square(4))# call the 'square' function with argument 3, store the result, then print itresult = square(3)print(result)
如果语句
if 语句计算一个条件(返回 true 或 false 的表达式)。
如果条件为 true,则执行 if 语句下的代码块。
elif :“else if”的缩写,它允许您检查多个条件。
当您有多个条件需要评估,并且您想要执行第一个 true 条件的代码块时,可以使用它。
else:如果前面的 if 或 elif 条件都不为 true,则 else 语句将运行一段代码。
# this script demonstrates the use of if-elif-else statements# set boolean variables for conditionsis_boy = trueis_handsome = false# check conditions using if-elif-else statementsif is_boy and is_handsome: print("you are a boy & youre handsome") print("hehe")elif is_boy and not (is_handsome): print("youre a boy but sorry not handsome")else: print("youre not a boy")
如果比较
此代码演示了 if 语句中的比较操作:
# this script demonstrates comparison operations in if statements# define a function to find the maximum of three numbersdef max_numbers(num1, num2, num3): if num1 >= num2 and num1 >= num3: return num1 elif num2 >= num1 and num2 >= num3: return num2 else: return num3# test the max_numbers function with different inputsprint(max_numbers(20, 40, 60))print(max_numbers(30, 14, 20))print(max_numbers(3, 90, 10))print("for min_number")# define a function to find the minimum of three numbersdef min_numbers(num1, num2, num3): if num1 <= num2 and num1 <= num3: return num1 elif num2 <= num1 and num2 <= num3: return num2 else: return num3# test the min_numbers function with different inputsprint(min_numbers(20, 40, 60))print(min_numbers(30, 14, 20))print(min_numbers(3, 90, 10))
猜谜游戏2
此脚本通过更多功能改进了猜谜游戏:
# this script improves the guessing game with more featuresimport random# generate a random number between 1 and 20secret_number = random.randint(1, 20)# initialize the number of attempts and set a limitattempts = 0attempt_limit = 5# loop to allow the user to guess the numberwhile attempts < attempt_limit: guess = int(input(f"guess the number (between 1 and 20). you have {attempt_limit - attempts} attempts left: ")) if guess == secret_number: print("congratulations! you guessed the number!") break elif guess < secret_number: print("too low!") else: print("too high!") attempts += 1# if the user does not guess correctly within the attempt limit, reveal the numberif guess != secret_number: print(f"sorry, the correct number was {secret_number}.")
for循环
for 循环用于迭代元素序列,例如列表、元组、字符串或范围。
这段代码引入了for循环:
# list of numbersnumbers = [1, 2, 3, 4, 5]# iterate over each number in the listfor number in numbers: # print the current number print(number)# output:# 1# 2# 3# 4# 5# list of friendsfriends = ["roi", "alex", "jimmy", "joseph", "kevin", "tony", "jimmy"]# iterate over each friend in the listfor friend in friends: # print the name of the current friend print(friend)# output:# roi# alex# jimmy# joseph# kevin# tony# jimmy# use range to generate numbers from 0 to 4for num in range(5): print(num)# output:# 0# 1# 2# 3# 4
指数函数
指数函数是一种数学函数,其中恒定基数被提升为可变指数。
此脚本展示了如何使用 math.pow 函数:
# this script demonstrates the use of the exponential functiondef exponentialfunction(base,power): result = 1 for index in range(power): result = result * base return resultprint(exponentialfunction(3,2))print(exponentialfunction(4,2))print(exponentialfunction(5,2))#or you can power just byprint(2**3) #number *** power
2d 列表和 for 循环
python 中的 2d 列表(或 2d 数组)本质上是列表的列表,其中每个子列表代表矩阵的一行。您可以使用嵌套的 for 循环来迭代 2d 列表中的元素。以下是使用 2d 列表和 for 循环的方法:
# This script demonstrates the use of 2D List and For Loops# Define a 2D list (list of lists)num_grid = [ [1, 2, 3], # Row 0: contains 1, 2, 3 [4, 5, 6], # Row 1: contains 4, 5, 6 [7, 8, 9], # Row 2: contains 7, 8, 9 [0] # Row 3: contains a single value 0]# Print specific elements in num_gridprint(num_grid[0][0]) # Print value in the zeroth row, zeroth column (value: 1)print(num_grid[1][0]) # Print value in the first row, zeroth column (value: 4)print(num_grid[2][2]) # Print value in the second row, second column (value: 9)print("using nested for loops")for row in num_grid : for col in row: print(col)
这就是我们如何使用 2d 列表和 for 循环。