一份Python代碼徹底入門Python，Simple and Rough！
註釋詳細~
參考代碼下載鏈接
from operator import itemgetter
from datetime import date, time, datetime, timedelta
from math import exp, log, sqrt
import re
#Print a simple string
print("Output #1 : I'm exited to learn Python.")
#兩個數值相加
x = 4
y = 5
z = x + y
print("Output #2 : Four plus five equals {0:d}.".format(z))
'''
輸出格式解釋
{} : 一個佔位符，表示這裏將要傳入print語句中的一個具體的值
0 : 指向format()方法中的第一個參數
: : 用來分隔傳入的值和它的格式
'''
#兩個列表相加
a = [1, 2, 3, 4]
b = ["first", "second", "third", "fourth"]
c = a + b
print("Output #3 : {0}, {1}, {2}".format(a, b, c))
#整數
x = 9
print("Output #4 : {0}".format(x))
print("Output #5 : {0}".format(3 ** 4))
print("Output #6 : {0}".format(int(8.3) / int(2.7)))
#浮點數
print("Output #7 : {0:.3f}".format(8.3 / 2.7)) #保留3位小數
y = 2.5 * 4.8
print("Output #8 : {0:.1f}".format(y)) #保留一位小數
r = 8 / float(3)
print("Output #9 : {0:.2f}".format(r)) #保留2位小數
print("Output #10 : {0:.4f}".format(8.0 / 3)) #保留4位小數
#調用math庫中的函數
print("Output #11 : {0:.4f}".format(exp(3))) #e^3
print("Output #12 : {0:.2f}".format(log(4))) #ln4
print("Output #13 : {0:.1f}".format(sqrt(81))) #平方根
#字符串
print("Output #14 : {0:s}".format('I\'m enjoying learning Python.'))
print("Output #15 : {0:s}".format("This is a long string. Without the backslash it \
would run off of the page on the right in the text \
editor and be very difficult to read and edit. \
By using the backslash you can split the long string \
into smaller strings on separate lines so that the whole string \
is easy to view in the text editor."))
print("Output #16 : {0:s}".format('''You can use triple single quotes for
multi-line comment strings.'''))
print("Output #17 : {0:s}".format("""You can also use triple double quotes for
multi-line comment strings."""))
string1 = "This is a " #定義字符串string1
string2 = "short string." #定義字符串string2
sentence = string1 + string2 #字符串連接
print("Output #18 : {0:s}".format(sentence))
print("Output #19 : {0:s} {1:s}{2:s}".format("she is", "very "*7, "beautiful."))
m = len(sentence) #字符串長度
print("Output #20 : {0:d}".format(m))
#split函數
string1 = "My deliverable is due in May"
string1_list1 = string1.split() #split默認用空格對字符串拆分
string1_list2 = string1.split(" ", 2) #2表示只用前兩個空格拆分，is due in May 被劃分到一起
print("Output #21 : {0}".format(string1_list1))
print("Output #22 : FIRST PIECE:{0} SECOND PIECE:{1} THIRD PIECE:{2}".format(string1_list2[0], string1_list2[1], string1_list2[2]))
string2 = "Your, deliverable, is, due, in, June"
string2_list = string2.split(",") #用,進行拆分
print("Output #23 : {0}".format(string2_list))
print("Output #24 : {0} {1} {2}".format(string2_list[1], string2_list[5], string2_list[-1]))
#join函數 組合拆分後的子字符串
print("Output #25 : {0}".format(",".join(string2_list)))
#strip函數 刪除指定不想要的字符
string3 = " Remove unwanted characters from this string.\t\t \n"
print("Output #26 : string3:{0:s}".format(string3)) #原始字符串
string3_lstrip = string3.lstrip()
print("Output #27 : lstrip:{0:s}".format(string3_lstrip)) #從左側刪除
string3_rstrip = string3.rstrip()
print("Output #28 : rstrip:{0:s}".format(string3_rstrip)) #從右側刪除
string3_strip = string3.strip()
print("Output #29 : strip:{0:s}".format(string3_strip)) #從兩側刪除
string4 = "$$Here\'s another string that has unwanted characters.__---++"
print("Output #30 : {0:s}".format(string4))
string4 = "$$The unwanted characters have been removed.__---++"
string4_strip = string4.strip('$_-+')
print("Output #31 : {0:s}".format(string4_strip))
#replace函數
string5 = "Let\'s replace the spaces in this sentence with other characters"
string5_replace = string5.replace(" ", "!@!")
print("Output #32 (with !@!) : {0:s}".format(string5_replace))
string5_replace = string5.replace(" ", ",")
print("Output #33 (with commas) : {0:s}".format(string5_replace))
#lower、upper、capitalize函數
string6 = "Here\'s WHAT Happens WHEN You Use lower."
print("Output #34 : {0:s}".format(string6.lower())) #將字符串字母變成小寫
string7 = "Here\'s what Happens when You Use UPPER."
print("Output #35 : {0:s}".format(string7.upper())) #將字符串字母大寫
string5 = "here\'s WHAT Happens WHEN you use Capitalize."
print("Output #36 : {0:s}".format(string5.capitalize())) #將字符串首字母大寫，其他字母小寫
string5_list = string5.split() #將字符串拆分
print("Output #37 (on each word) : ") #將拆分後的子字符串首字母大寫，其他字母小寫
for word in string5_list:
print("{0:s}".format(word.capitalize()))
#正則表達式與模式匹配
string = "The quick brown fox jumps over the lazy dog."
string_list = string.split()
pattern = re.compile(r"The", re.I) #re.I確保模式不區分大小寫
count = 0
for word in string_list:
if pattern.search(word):
count += 1
print("Output #38 : {0:d}".format(count))
#在字符串中每次找到模式時將其打印出來
string = "The quick brown fox jumps over the lazy dog."
string_list = string.split()
pattern = re.compile(r"(?P<match_word>The)", re.I)
print("Output #39 : ")
for word in string_list:
if pattern.search(word):
print("{:s}".format(pattern.search(word).group('match_word')))
#使用字母“a”替換替換字符串中的the
string = "The quick brown fox jumps over the lazy dog."
string_to_find = r"The"
pattern = re.compile(string_to_find, re.I)
print("Output #40 : {:s}".format(pattern.sub("a", string)))
#日期
#打印今天的日期，以及年月日
today = date.today()
print("Output #41 : today : {0!s}".format(today))
print("Output #42 : {0!s}".format(today.year))
print("Output #43 : {0!s}".format(today.month))
print("Output #44 : {0!s}".format(today.day))
current_datetime = datetime.today()
print("Output #45 : {0!s}".format(current_datetime))
#使用datedelta計算一個新日期
one_day = timedelta(days=-1)
yesterday = today + one_day
print("Output #46 : yesterday : {0!s}".format(yesterday))
eight_hours = timedelta(hours=-8)
print("Output #47 : {0!s} {1!s}".format(eight_hours.days, eight_hours.seconds))
#計算出兩個日期之間的天數
date_diff = today - yesterday
print("Output #48 : {0!s}".format(date_diff))
print("Output #49 : {0!s}".format(str(date_diff).split()[0]))
#根據一個日期對象創建一個特定格式的字符串
print("Output #50 : {:s}".format(today.strftime('%m/%d/%Y')))
print("Output #51 : {:s}".format(today.strftime('%b %d %Y')))
print("Output #52 : {:s}".format(today.strftime('%Y-%m-%d')))
print("Output #53 : {:s}".format(today.strftime('%B %d,%Y')))
#根據一個表示日期的字符串
#創建一個帶有特殊格式的datetime對象
date1 = today.strftime('%m/%d/%Y')
date2 = today.strftime('%b %d,%Y')
date3 = today.strftime('%Y-%m-%d')
date4 = today.strftime('%B %d,%Y')
#基於四個具有不同日期格式的字符串
#創建兩個datetime對象和兩個date對象
print("Output #54 : {!s}".format(datetime.strptime(date1, '%m/%d/%Y')))
print("Output #55 : {!s}".format(datetime.strptime(date2, '%b %d,%Y')))
#僅顯示日期部分
print("Output #56 : {!s}".format(datetime.date(datetime.strptime(date3, '%Y-%m-%d'))))
print("Output #57 : {!s}".format(datetime.date(datetime.strptime(date4, '%B %d,%Y'))))
#創建列表
a_list = [1, 2, 3]
print("Output #58 : {}".format(a_list))
print("Output #59 : a_list has {} elements.".format(len(a_list)))
print("Output #60 : the maximum value in a_list is {}.".format(max(a_list)))
print("Output #61 : the minimum value in a_list is {}.".format(min(a_list)))
another_list = ['printer', 5, ['star', 'circle', 5]]
print("Output #62 : {}".format(another_list))
print("Output #63 : another_list also has {} elements.".format(len(another_list)))
print("Output #64 : 5 is in another_list {} time.".format(another_list.count(5)))
#索引值
print("Output #65 : {}".format(a_list[0]))
print("Output #66 : {}".format(a_list[1]))
print("Output #67 : {}".format(a_list[2]))
print("Output #68 : {}".format(a_list[-1]))
print("Output #69 : {}".format(a_list[-2]))
print("Output #70 : {}".format(a_list[-3]))
print("Output #71 : {}".format(another_list[2]))
print("Output #72 : {}".format(another_list[-1]))
#列表切片
print("Output #73 : {}".format(a_list[0:2]))
print("Output #74 : {}".format(another_list[:2]))
print("Output #75 : {}".format(a_list[1:3]))
print("Output #76 : {}".format(another_list[1:]))
#複製列表
a_new_list = a_list[:]
print("Output #77 : {}".format(a_new_list))
#列表連接
a_long_list = a_list + another_list
print("Output #78 : {}".format(a_long_list))
#使用in與not in
a = 2 in a_list
print("Output #79 : {}".format(a))
if 2 in a_list:
print("Output #80 : 2 is in {}.".format(a_list))
b = 6 not in a_list
print("Output #81 : {}".format(b))
if 6 not in a_list:
print("Output #82 : 6 is not in {}".format(a_list))
#追加、刪除和彈出元素
a_list.append(4)
a_list.append(5)
a_list.append(6)
print("Output #83 : {}".format(a_list))
a_list.remove(5)
print("Output #84 : {}".format(a_list))
a_list.pop()
a_list.pop()
print("Output #85 : {}".format(a_list))
#列表反轉
a_list.reverse()
print("Output #86 : {}".format(a_list))
a_list.reverse()
print("Output #87 : {}".format(a_list))
#列表排序
unordered_list = [3, 5, 1, 7, 2, 8, 4, 9, 0, 6]
print("Output #88 : {}".format(unordered_list))
list_copy = unordered_list[:]
list_copy.sort()
print("Output #89 : {}".format(list_copy))
print("Output #90 : {}".format(unordered_list))
#sort排序函數
my_lists = [[1, 2, 3, 4], [4, 3, 2, 1], [2, 4, 1, 3]]
my_lists_sorted_by_index_3 = sorted(my_lists, key=lambda index_value:index_value[3])
print("Output #91 : {}".format(my_lists_sorted_by_index_3))
#使用itemgetter()對列表集合按照兩個索引位置來排序
my_lists = [[123, 2, 2, 444], [22, 6, 6, 444], [354, 4, 4, 678], [236, 5, 5, 678], [578, 1, 1, 290], [461, 1, 1, 290]]
my_lists_sorted_by_index_3_and_0 = sorted(my_lists, key=itemgetter(3, 0))
print("Output #92 : {}".format(my_lists_sorted_by_index_3_and_0))
#元組
#創建元組
my_tuple = ('x', 'y', 'z')
print("Output #93 : {}".format(my_tuple))
print("Output #94 : my_tuple has {} elements".format(len(my_tuple)))
print("Output #95 : {}".format(my_tuple[1]))
longer_tuple = my_tuple + my_tuple
print("Output #96 : {}".format(longer_tuple))
#元組解包
one, two, three = my_tuple
print("Output #97 : {0} {1} {2}".format(one, two, three))
var1 = 'red'
var2 = 'robin'
print("Output #98 : {} {}".format(var1, var2))
var1, var2 = var2, var1 #元組彼此交換
print("Output #99 : {} {}".format(var1, var2))
#元組轉換成列表
my_list = [1, 2, 3]
my_tuple = ('x', 'y', 'z')
print("Output #100 : {}".format(tuple(my_list)))
print("Output #101 : {}".format(tuple(my_tuple)))
#字典
empty_dict = { }
a_dict = {'one':1, 'two':2, 'three':3}
print("Output #102 : {}".format(a_dict))
print("Output #103 : a_dict has {!s} elements".format(len(a_dict)))
another_dict = {'x':'printer', 'y':5, 'z':['star', 'circle', 9]}
print("Output #104 : {}".format(another_dict))
print("Output #105 : another_dict also has {!s} elements".format(len(another_dict)))
#使用鍵來引用字典中特定的值
print("Output #106 : {}".format(a_dict['two']))
print("Output #107 : {}".format(another_dict['z']))
#使用copy複製一個字典
a_new_dict = a_dict.copy()
print("Output #108 : {}".format(a_new_dict))
#使用keys、 value、items
print("Output #109 : {}".format(a_dict.keys()))
a_dict_keys = a_dict.keys()
print("Output #110 : {}".format(a_dict_keys))
print("Output #111 : {}".format(a_dict.values()))
print("Output #112 : {}".format(a_dict.items()))
print("Output #113 : {}".format(a_dict.keys()))
#使用判斷關鍵字
if 'y' in another_dict:
print("Output #114 : y is a key in another_dict : {}".format(another_dict.keys()))
if 'c' not in another_dict:
print("Output #115 : c is not a key in another_dict : {}".format(another_dict.keys()))
print("Output #116 : {!s}".format(a_dict.get('three')))
print("Output #117 : {!s}".format(a_dict.get('four')))
print("Output #118 : {!s}".format(a_dict.get('four', 'Not in dict')))
#排序
print("Output #119 : {}".format(a_dict))
dict_copy = a_dict.copy()
ordered_dict1 = sorted(dict_copy.items(), key=lambda item:item[1])
print("Output #120 : (order by keys) : {}".format(ordered_dict1))
ordered_dict2 = sorted(dict_copy.items(), key=lambda item:item[1])
print("Output #121 : (order by keys) : {}".format(ordered_dict1))
ordered_dict3 = sorted(dict_copy.items(), key=lambda x:x[1], reverse=True)
print("Output #122 : (order by values, descending) : {}".format(ordered_dict3))
ordered_dict4 = sorted(dict_copy.items(), key=lambda x:x[1], reverse=False)
print("Output #123 : (order by values, ascending) : {}".format(ordered_dict4))
#控制流
#if-else判斷
x = 5
if x > 4 or x != 9:
print("Output #124: {}".format(x))
else:
print("Output #125: x is not greater than 4")
# if-elif-else 判斷
if x > 6:
print("Output #126: x is greater than six")
elif x > 4 and x == 5:
print("Output #127: {}".format(x*x))
else:
print("Output #128: x is not greater than 4")
# for 循環
y = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
z = ['Annie', 'Betty', 'Claire', 'Daphne', 'Ellie', 'Franchesca', 'Greta', 'Holly', 'Isabel', 'Jenny']
print("Output #129:")
for month in y:
print("{!s}".format(month))
print("Output #130: (index value: name in list)")
for i in range(len(z)):
print("{0!s}: {1:s}".format(i, z[i]))
print("Output #131: (access elements in y with z's index values)")
for j in range(len(z)):
if y[j].startswith('J'):
print("{!s}".format(y[j]))
print("Output #132:")
for key, value in another_dict.items():
print("{0:s}, {1}".format(key, value))
#for循環的簡化
my_data = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
rows_to_keep = [row for row in my_data if row[2] > 5] #for循環的簡化方式
print("Output #133 (list comprehension): {}".format(rows_to_keep))
my_data = [(1, 2, 3), (4, 5, 6), (7, 8, 9), (7, 8, 9)]
set_of_tuples1 = {x for x in my_data}
print("Output #134 (set comprehension): {}".format(set_of_tuples1))
set_of_tuples2 = set(my_data)
print("Output #135 (set function): {}".format(set_of_tuples2))
my_dictionary = {'customer1': 7, 'customer2': 9, 'customer3': 11}
my_results = {key: value for key, value in my_dictionary.items() if value > 10}
print("Output #136 (dictionary comprehension): {}".format(my_results))
# while循環
print("Output #137:")
x = 0
while x < 11:
print("{!s}".format(x))
x += 1
# 函數定義
def getMean(numericValues):
return sum(numericValues)/len(numericValues) if len(numericValues) > 0 else float('nan')
my_list = [2, 2, 4, 4, 6, 6, 8, 8]
print("Output #138 (mean): {!s}".format(getMean(my_list)))
# 異常
def getMean(numericValues):
return sum(numericValues)/len(numericValues)
my_list2 = [ ]
# 簡單版本
try:
print("Output #139: {}".format(getMean(my_list2)))
except ZeroDivisionError as detail:
print("Output #139 (Error): {}".format(float('nan')))
print("Output #139 (Error): {}".format(detail))
# 複雜版本
try:
result = getMean(my_list2)
except ZeroDivisionError as detail:
print("Output #140 (Error): {}".format(float('nan')))
print("Output #140 (Error): {}".format(detail))
else:
print("Output #140 (The mean is): {}".format(result))
finally:
print("Output #140 (Finally): The finally block is executed every time")