一豆瘫、作業(yè)內(nèi)容
笨辦法學 Python 習題0-10以及加分題。
二菊值、作業(yè)代碼:
習題 0就是上一篇文章外驱，【Python爬蟲】-第一個腳本
# 習題 1: 第一個程序
print("Hello World!")
print("Hello Again")
print("I like typing this.")
print("This is fun.")
print("Yay! printing.")
print("I'd much rather you 'not'.")
print('I "said" do not touch this.')
# 加分習題
# 一、讓你的腳本再多打印一行腻窒。
# 使用 \n 換單行
print('I "said" do not\ntouch this.')
# 使用三引號'''...''' 換多行
print('''I
"said"
do
not
touch
this.''''')
# 二昵宇、讓你的腳本只打印一行。
print("Hello World!")
print("Hello Again")
print("I like typing this.")
# 刪除其他的print儿子，將多個字符串合并為一個字符串瓦哎，用反斜杠表示字符串將在下一行繼續(xù)，并只打印一行
print("Hello World! \
Hello Again. \
I like typing this.")
# 三柔逼、在一行的起始位置放一個 ‘#’ (octothorpe) 符號蒋譬。它的作用是什么？自己研究一下愉适。
# print("Hello World!")
‘#’ 的作用是注釋犯助。從運行的結果來看，如果不想讓代碼起到作用维咸，又不想刪除代碼也切，也可以使用注釋符號。
在《簡明 Python 教程》中腰湾，是這么說明的：
你應該在你的程序中盡可能多地使用有用的注釋：
- 解釋假設
- 說明重要的決定
- 解釋重要的細節(jié)
- 說明你想要解決的問題
- 說明你想要在程序中克服的問題雷恃，等等。
# 習題 2: 注釋和井號
# A comment, this is so you can read your program later.
# Anything after the # is ignored by python.
print("I could have code like this.") # and the comment after is ignored
# You can also use a comment to "disable" or comment out a piece of code:
# print("This won't run.")
print("This will run.")
加分習題
# 一费坊、弄清楚”#”符號的作用倒槐。而且記住它的名字。(中文為井號附井，英文為 octothorpe 或者 pound character)讨越。
# 二两残、打開你的 ex2.py 文件，從后往前逐行檢查把跨。從最后一行開始人弓，倒著逐個單詞單詞檢查回去。
# 三着逐、有沒有發(fā)現(xiàn)什么錯誤呢崔赌？有的話就改正過來.
# 四、朗讀你寫的習題耸别，把每個字符都讀出來健芭。有沒有發(fā)現(xiàn)更多的錯誤呢？有的話也一樣改正過來秀姐。
習題 3: 數(shù)字和數(shù)學計算
# 打印字符串 I will now count my chickens:
print("I will now count my chickens:")
# 打印字符串 Hens和30 除以 6慈迈，輸出的浮點數(shù)與25相加的結果
print("Hens", 25 + 30 / 6)
# 打印字符串 Roosters，給出25與3的乘積省有，并將乘積返回除法運算后的余數(shù)
print("Roosters", 100 - 25 * 3 % 4)
# 打印字符串 Now I will count the eggs:
print("Now I will count the eggs:")
# 打印 運算的結果
print(3 + 2 + 1 - 5 + 4 % 2 - 1 / 4 + 6)
# 打印字符串 Is it true that 3 + 2 < 5 - 7?
print("Is it true that 3 + 2 < 5 - 7?")
# 打印 運算結果的布爾值
print(3 + 2 < 5 - 7)
# 打印字符串 What is 3 + 2? 和整數(shù)3與整數(shù)2相加運算的結果
print("What is 3 + 2?", 3 + 2)
# 打印字符串 What is 5 - 7 和整數(shù)5與整數(shù)7相減運算的結果
print("What is 5 - 7?", 5 -7)
# 打印字符串 Oh, that's why it's False.
print("Oh, that's why it's False.")
# 打印字符串 How about some more.
print("How about some more.")
# 打印字符串 Is it greater? 和布爾值
print("Is it greater?", 5 > -2)
# 打印字符串 Is it greater or equal? 和布爾值
print("Is it greater or equal?", 5 >= -2)
# 打印字符串 Is it less or equal? 和布爾值
print("Is it less or equal?", 5 <= -2)
# 加分習題
# 一痒留、使用 # 在代碼每一行的前一行為自己寫一個注解，說明一下這一行的作用蠢沿。
# 注解已在上方的輸入內(nèi)容中伸头。
# 二、記得開始時的 <練習 0> 吧搏予？用里邊的方法把 Python 運行起來熊锭，然后使用剛才學到的運算符號，把Python當做計算器玩玩雪侥。
>>> 10 / 3
3.3333333333333335
>>> 9 / 3
3.0
>>> 10 // 3
3
>>> 10 % 3
1
# 三碗殷、自己找個想要計算的東西，寫一個 .py 文件把它計算出來速缨。
# 略锌妻。
# 四、有沒有發(fā)現(xiàn)計算結果是”錯”的呢旬牲？計算結果只有整數(shù)仿粹，沒有小數(shù)部分。研究一下這是為什么原茅，搜索一下“浮點數(shù)(floating point number)”是什么東西吭历。
# 浮點數(shù)也就是小數(shù)，之所以稱為浮點數(shù)擂橘。
# 是因為按照科學記數(shù)法表示時晌区，一個浮點數(shù)的小數(shù)點位置是可變的。
# 五、使用浮點數(shù)重寫一遍 ex3.py朗若，讓它的計算結果更準確(提示: 20.0 是一個浮點數(shù))恼五。
print("I will now count my chickens:")
print("Hens", 25 + 30 / 6)
print("Roosters", 100 - 25 * 3.0 % 4)
print("Now I will count the eggs:")
print(3 + 2 + 1 - 5 + 4 % 2 - 1 / 4 + 6)
print("Is it true that 3.0 + 2.0 < 5.0 - 7.0?")
print(3.0 + 2.0 < 5.0 - 7.0)
print("What is 3.0 + 2.0?", 3.0 + 2)
print("What is 5.0 - 7.0?", 5.0 -7.0)
print("Oh, that's why it's False.")
print("How about some more.")
print("Is it greater?", 5.0 > -2.0)
print("Is it greater or equal?", 5.0 >= -2.0)
print("Is it less or equal?", 5.0 <= -2.0)
# 習題 4: 變量(variable)和命名
# 輸入習題中的內(nèi)容。在每一行的上面寫一行注解哭懈，給自己解釋一下這一行的作用灾馒。 倒著讀你的 .py 文件。
# 朗讀你的 .py 文件遣总，將每個字符也朗讀出來睬罗。
# cars 是整數(shù)
cars = 100
# space_in_a_car 是浮點數(shù)
space_in_a_car = 4.0
# drivers 是整數(shù)
drivers = 30
# passengers 是整數(shù)
passengers = 90
# 從 cars 中減去 drivers,輸出的結果賦值給變量 cars_not_driven
cars_not_driven = cars - drivers
# 把變量 drivers 賦值給變量 cars_driven
cars_driven = drivers
# 給出 cars_driven 和 space_in_a_car 的乘積，并賦值給變量 carpool_capacity
carpool_capacity = cars_driven * space_in_a_car
# passengers 除以 cars_driven彤避，輸出的結果賦值給變量 average_passengers_per_car
average_passengers_per_car = passengers / cars_driven
# 打印字符串 There are傅物，變量 cars 和字符串 cars available.
print("There are", cars, "cars available.")
# 打印字符串 There are only夯辖，變量 drivers 和字符串 drivers available.
print("There are only", drivers, "drivers available.")
# 打印字符串 There will be琉预，變量 cars_not_driven 和字符串 empty cars today.
print("There will be", cars_not_driven, "empty cars today.")
# 打印字符串 We can transport，變量 carpool_capacity 和字符串 people today.
print("We can transport", carpool_capacity, "people today.")
# 打印字符串 We have蒿褂，變量 passengers 和字符串 to carpool today.
print("We have", passengers, "to carpool today.")
# 打印字符串 We need to put about,變量 average_passengers_per_car 和字符串 in each car.
print("We need to put about", average_passengers_per_car, "in each car.")
# 更多的加分習題:
# 一圆米、我在程序里用了 4.0 作為 space_in_a_car 的值，這樣做有必要嗎啄栓？如果只用 4 會有什么問題?
# 修改了編輯器的代碼娄帖，觀察運行的結果并得出結論：有必要。如果只用4昙楚，得到的結果就不是浮點數(shù)了近速。因為4.0是一個浮點數(shù)，4是一個整數(shù)堪旧。
# 二削葱、記住 4.0 是一個“浮點數(shù)”，自己研究一下這是什么意思淳梦。
# 浮點數(shù)就是小數(shù)析砸，按照科學計數(shù)法來表示時，一個浮點數(shù)的小數(shù)點位置是可變的爆袍。
# 三首繁、在每一個變量賦值的上一行加上一行注解。
# 每一個變量賦值的注解已添加在上方的輸入內(nèi)容中陨囊。
# 四弦疮、記住 = 的名字是等于(equal)，它的作用是為東西取名蜘醋。
# 五胁塞、記住 _ 是下劃線字符(underscore)。
# 六、將 python 作為計算器運行起來闲先，就跟以前一樣状土，不過這一次在計算過程中使用變量名來做計算，常見的變量名有 i, x, j 等等伺糠。
>>> i = 100
>>> x = 4.0
>>> j = 30
>>> r = 90
>>> cars_not_driven = i - j
>>> cars_driven = j
>>> carpool_capacity = cars_driven * x
>>> average_passengers_per_car = r / cars_driven
>>>
>>>
>>> print("There are", i, "cars available.")
There are 100 cars available.
>>> print("There are only", j, "drivers available.")
There are only 30 drivers available.
>>> print("There will be", cars_not_driven, "empty cars today.")
There will be 70 empty cars today.
>>> print("We can transport", carpool_capacity, "people today.")
We can transport 120.0 people today.
>>> print("We have", 90, "to carpool today.")
We have 90 to carpool today.
>>> print("We need to put about", average_passengers_per_car, "in each car.")
We need to put about 3.0 in each car.
# 習題 5: 更多的變量和打印
my_name = 'Zed A. Shaw'
my_age = 35 # not a lie
my_height = 74 # inches
my_weight = 180 # lbs
my_eyes = 'Blue'
my_teeth = 'White'
my_hair = 'Brown'
print("Let's talk about %s." % my_name)
print("He's %s inches tall." % my_height)
print("He's %d pounds heavy." % my_weight)
print("Actually that's not too heavy.")
print("He's got %s eyes and %s hair." % (my_eyes, my_hair))
print("His teeth are usually %s depending on the coffee." % my_teeth)
# this line is tricky, try to get it exactly right
print("If I add %d, %d, and %d I get %d." % (
my_age, my_height, my_weight, my_age + my_height + my_weight))
# 加分習題
# 一蒙谓、修改所有的變量名字，把它們前面的``my_``去掉训桶。確認將每一個地方的都改掉累驮，不只是你使用``=``賦值過的地方。
# 二舵揭、試著使用更多的格式化字符谤专。例如`` %r ``就是是非常有用的一個，它的含義是“不管什么都打印出來”午绳。
name = 'Zed A. Shaw'
age = 35 # not a lie
height = 74 # inches
weight = 180 # lbs
eyes = 'Blue'
teeth = 'White'
hair = 'Brown'
print("Let's talk about %r." % name)
print("He's %r inches tall." % height)
print("He's %r pounds heavy." % weight)
print("Actually that's not too heavy.")
print("He's got %r eyes and %r hair." % (eyes, hair))
print("His teeth are usually %r depending on the coffee." % teeth)
# this line is tricky, try to get it exactly right
print("If I add %r, %r, and %r I get %r." % (
age, height, weight, age + height + weight))
# 三置侍、在網(wǎng)上搜索所有的 Python 格式化字符。
# Python 格式化字符：
# 整數(shù)
%d
# 浮點數(shù)
%f
# 字符串
%s
# 十六進制整數(shù)
%x
# 四拦焚、試著使用變量將英寸和磅轉(zhuǎn)換成厘米和千克蜡坊。不要直接鍵入答案。使用 Python 的計算功能來完成赎败。
height = 74 # inches
weight = 180 # lbs
transfer_height = 2.54 * height # cm
transfer_weight = 0.4535924 * weight # kg
print("He's %r inches tall, %r cm." % (height, transfer_height))
print("He's %r pounds heavy, %r kg." % (weight, transfer_weight))
# 習題 6: 字符串(string)和文本
x = "There are %d types of people." % 10
binary = "binary"
do_not = "don't"
y = "Those who know %s and those who %s." % (binary, do_not)
print(x)
print(y)
print("I said: %r." % x)
print("I also said: '%s'." % y)
hilarious = False
joke_evaluation = "Isn't that joke so funny?! %r"
print(joke_evaluation % hilarious)
w = "This is the left side of..."
e = "a string with a right side."
print(w + e)
# 加分習題
# 一秕衙、通讀程序，在每一行的上面寫一行注解僵刮，給自己解釋一下這一行的作用据忘。
# 把格式化的變量 %d 放進字符串 There are types of people. 并把字符串賦值給變量 x，變量名為10
x = "There are %d types of people." % 10
# 把字符串 binary 賦值給變量 binary
binary = "binary"
# 把字符串 don't 賦值給變量 do_not
do_not = "don't"
# 把兩個格式化的變量 %s 放進字符串 Those who know and those who. 并把字符串賦值給變量 y搞糕，變量名分別為binary勇吊，do_not
y = "Those who know %s and those who %s." % (binary, do_not)
# 打印變量 x
print(x)
# 打印變量 y
print(y)
# 打印含有格式化變量 %r 的字符串 I said: 變量名為 x
print("I said: %r." % x)
# 打印含有格式化變量 %s 的字符串 I also said: 變量名為 y
print("I also said: '%s'." % y)
# 變量 hilarious 是一個布爾值 False
hilarious = False
# 把格式化的變量 %r 放進字符串 Isn't that joke so funny?! 并把字符串賦值給變量 joke_evaluation
joke_evaluation = "Isn't that joke so funny?! %r"
# 打印變量 joke_evaluation ，變量名為 hilarious
print(joke_evaluation % hilarious)
# 將字符串 This is the left side of... 賦值給變量 w
w = "This is the left side of..."
# 將字符串 a string with a right side. 賦值給變量 e
e = "a string with a right side."
# 打印變量 w 和變量 e
print(w + e)
# 二寞宫、找到所有的”字符串包含字符串”的位置萧福，總共有四個位置。
# 1辈赋、字符串 Those who know %s and those who %s.中包含名為 binary 的格式化變量%s鲫忍，而變量 binary 包含字符串 binary
# 2、字符串 Those who know %s and those who %s.中包含名為 do_not 的格式化變量%s钥屈，而變量 do_not 包含字符串 don't
binary = "binary"
do_not = "don't"
y = "Those who know %s and those who %s." % (binary, do_not)
# 3悟民、字符串 There are %d types of people. 被賦值給變量x，而字符串 I said: %r.包含名為 x 的格式化變量 %r篷就。
x = "There are %d types of people." % 10
print("I said: %r." % x)
# 4射亏、字符串 Those who know %s and those who %s.被賦值給變量y，而字符串 I also said: '%s'.包含名為 y 的格式化變量 %s
print("I also said: '%s'." % y)
# 三、你確定只有四個位置嗎智润？你怎么知道的及舍？沒準我在騙你呢。
# 我檢查了一下窟绷，應該是四個位置……
# 四锯玛、解釋一下為什么 w 和 e 用 + 連起來就可以生成一個更長的字符串。
# 通過觀察輸入的內(nèi)容：
# 將字符串 This is the left side of... 賦值給變量 w
w = "This is the left side of..."
# 將字符串 a string with a right side. 賦值給變量 e
e = "a string with a right side."
# 打印變量 w 和變量 e
print(w + e)
# 得出結論：因為字符串不是整數(shù)兼蜈、浮點數(shù)攘残，不能通過相加運算。
# 習題 7: 更多打印
print("Mary had a little lamb.")
print("Its fleece was white as %s." % 'snow')
print("And everywhere that Mary went.")
print("." * 10) # what'd that do?
end1 = "C"
end2 = "h"
end3 = "e"
end4 = "e"
end5 = "s"
end6 = "e"
end7 = "B"
end8 = "u"
end9 = "r"
end10 = "g"
end11 = "e"
end12 = "r"
# watch that comma at the end. try removing it to see that happens
print(end1 + end2 + end3 + end4 + end5 + end6,)
print(end7 + end8 + end9 + end10 + end11 + end12)
這里有一個疑惑的地方为狸，因為教程里的標準答案（運行的結果）是：
$ python ex7.py
Mary had a little lamb.
Its fleece was white as snow.
And everywhere that Mary went.
..........
Cheese Burger
$
Cheese Burger 只打印了一行……不知道是不是Python 2 和Python 3 的區(qū)別歼郭？
# 加分習題
# 一、逆向閱讀辐棒，在每一行的上面加一行注解病曾。
# 打印字符串 Mary had a little lamb.
print("Mary had a little lamb.")
# 打印包含格式化變量 %s的字符串 Its fleece was white as %s. 變量名為字符串snow
print("Its fleece was white as %s." % 'snow')
# 打印字符串 And everywhere that Mary went.
print("And everywhere that Mary went.")
# 打印字符串.重復10次數(shù)后的結果
print("." * 10) # what'd that do?
# 將字符串 C 賦值給變量 end1
end1 = "C"
# 將字符串 h 賦值給變量 end2
end2 = "h"
# 將字符串 e 賦值給變量 end3
end3 = "e"
# 將字符串 e 賦值給變量 end4
end4 = "e"
# 將字符串 s 賦值給變量 end5
end5 = "s"
# 將字符串 e 賦值給變量 end6
end6 = "e"
# 將字符串 B 賦值給變量 end7
end7 = "B"
# 將字符串 u 賦值給變量 end8
end8 = "u"
# 將字符串 r 賦值給變量 end9
end9 = "r"
# 將字符串 g 賦值給變量 end10
end10 = "g"
# 將字符串 e 賦值給變量 end11
end11 = "e"
# 將字符串 r 賦值給變量 end12
end12 = "r"
# watch that comma at the end. try removing it to see that happens
# 因'a' + 'b' 則輸出 'ab' 所以打印出變量 end1 至 變量 end6 的值，也就是字符串
print(end1 + end2 + end3 + end4 + end5 + end6,)
# 因'a' + 'b' 則輸出 'ab' 所以打印出變量 end7 至變量 end12 的值涉瘾，也就是字符串
print(end7 + end8 + end9 + end10 + end11 + end12)
# 二知态、倒著朗讀出來捷兰，找出自己的錯誤立叛。
# 三、從現(xiàn)在開始贡茅，把你的錯誤記錄下來秘蛇，寫在一張紙上。
# 四顶考、在開始下一節(jié)習題時赁还，閱讀一遍你記錄下來的錯誤，并且盡量避免在下個練習中再犯同樣的錯誤驹沿。
# 五艘策、記住，每個人都會犯錯誤渊季。程序員和魔術師一樣朋蔫，他們希望大家認為他們從不犯錯，不過這只是表象而已却汉，他們每時每刻都在犯錯驯妄。
## 習題 8: 打印，打印
formatter = "%r %r %r %r"
print(formatter % (1, 2, 3, 4))
print(formatter % ("one", "two", "three", "four"))
print(formatter % (True, False, False, True))
print(formatter % (formatter, formatter, formatter, formatter))
print(formatter % (
"I had this thing.",
"That you could type up right.",
"But it didn't sing.",
"So I said goodnight."
))
# 加分習題
# 一合砂、自己檢查結果青扔，記錄你犯過的錯誤，并且在下個練習中盡量不犯同樣的錯誤。
# 二微猖、注意最后一行程序中既有單引號又有雙引號谈息，你覺得它是如何工作的？
# 不清楚凛剥。
## 習題 9: 打印黎茎，打印，打印
# Here's some new strange stuff, remember type it exactly.
days = "Mon Tue Wed Thu Fri Sat Sun"
months = "Jan\nFeb\nMar\nApr\nMay\nJun\nJul\nAug"
print("Here are the days: ", days)
print("Here are the months: ", months)
print("""
There's something going on here.
With the three double-quotes.
We'll be able to type as much as we like.
Even 4 lines if we want, or 5, or 6.
""")
# 加分習題
# 一当悔、自己檢查結果傅瞻，記錄你犯過的錯誤，并且在下個練習中盡量不犯同樣的錯誤盲憎。
# 習題 10: 那是什么嗅骄？
tabby_cat = "\tI'm tabbed in."
persian_cat = "I'm split\non a line."
backslash_cat = "I'm \\ a \\ cat."
fat_cat = """
I'll do a list:
\t* Cat food
\t* Fishies
\t* Catnip\n\t* Grass
"""
print(tabby_cat)
print(persian_cat)
print(backslash_cat)
print(fat_cat)
# 加分習題
# 一、上網(wǎng)搜索一下還有哪些可用的轉(zhuǎn)義字符饼疙。
# 續(xù)行符溺森，用于行尾
\
# 反斜杠符號
\\
# 單引號
\'
# 雙引號
\"
# 響鈴
\a
# 退格
\b
# 轉(zhuǎn)義
\e
# 空
\000
# 換行
\n
# 縱向制表符
\v
# 橫向制表符
\t
# 回車
\r
# 換頁
\f
# 八進制數(shù)yy代表的字符，例如：\o12代表換行
\oyy
# 十進制yy代表的字符窑眯，例如：\x0a代表換行
\xyy
# 其他的字符以普通格式輸出
\other
# 二屏积、使用 ''' (三個單引號)取代三個雙引號，看看效果是不是一樣的磅甩？
fat_cat = '''
I'll do a list:
\t* Cat food
\t* Fishies
\t* Catnip\n\t* Grass
'''
print(fat_cat)
# 效果是一樣的炊林。
# 三、將轉(zhuǎn)義序列和格式化字符串放到一起卷要，創(chuàng)建一種更復雜的格式渣聚。
# 將包含格式化變量 %r 的字符串賦值給 變量formatter
formatter = "%r\n%r\000%r\'%r"
# 變量formatter的變量名分別為字符串 one、字符串two 僧叉、字符串 three和字符串 four
# 打印變量 formatter
print(formatter % ("one", "two", "three", "four"))
# 四奕枝、記得 %r 格式化字符串嗎？
# 使用 %r 搭配單引號和雙引號轉(zhuǎn)義字符打印一些字符串出來瓶堕。
# 將 %r 和 %s 比較一下隘道。 注意到了嗎？%r 打印出來的是你寫在腳本里的內(nèi)容郎笆，而 %s 打印的是你應該看到的內(nèi)容谭梗。
# 將包含格式化變量 %r 的字符串賦值給 變量formatter
formatter = "%r\n%r\"%r\'%r"
print(formatter % (1, 2, 3, 4))
# 變量formatter的變量名分別為字符串 one、字符串two 题画、字符串 three和字符串 four
# 打印變量 formatter
print(formatter % ("one", "two", "three", "four"))
print(formatter % (True, False, False, True))
print(formatter % (formatter, formatter, formatter, formatter))
print(formatter % (
"I had this thing.",
"That you could type up right.",
"But it didn't sing.",
"So I said goodnight."
))
# 將包含格式化變量 %s 的字符串賦值給 變量formatter
formatter = "%s\n%s\"%s\'%s"
print(formatter % (1, 2, 3, 4))
# 變量formatter的變量名分別為字符串 one默辨、字符串two 、字符串 three和字符串 four
# 打印變量 formatter
print(formatter % ("one", "two", "three", "four"))
print(formatter % (True, False, False, True))
print(formatter % (formatter, formatter, formatter, formatter))
print(formatter % (
"I had this thing.",
"That you could type up right.",
"But it didn't sing.",
"So I said goodnight."
))
# 對整數(shù)苍息、布爾值缩幸、沒有影響壹置。
# 對字符串有影響。
三表谊、學習總結
總結中钞护，遲些時候再補上。
