1. Python的hello-world：
print ("Hello, Python!")缭乘、
完了 搖就完事兒了·
2. Python怎么表達程序塊：
不需要{}捏雌，用不同的換行表示
像這樣
3. Python如何表示多行語句：
如果正常語句要換行：
后面加\ ? ? ? ? ? ? ?像這樣：
如果是【】之類的括號里面的不需要加\
4. Python怎么引用外界的東西：
單詞用一個‘ ? ? ? ? ? ? ’
句子用兩個‘’ ? ? ? ? ? ? ? ?‘’
段落用三個‘’‘ ? ? ? ? ? ? ? ’‘’
5. Python如何添加注釋：
用#后面接東西
Python不支持多行注釋
所以得一行一個#
6. 創(chuàng)建空白行：
/n植袍， 空白行在程序里不識別
7. 讓程序等待用戶操作：
input("\n\nPress the enter key to exit.")
可以把程序窗口保持直到用戶輸入指定按鍵
8. 干什么的稿黍？沒懂
9. options.py:
#!/usr/bin/python3
import sys, getopt
def main(argv):
inputfile = ''
outputfile = ''
try:
opts, args = getopt.getopt(argv,"hi:o:",["ifile=","ofile="])
except getopt.GetoptError:
print ('test.py -i -o ')
sys.exit(2)
for opt, arg in opts:
if opt == '-h':
print ('test.py -i -o ')
sys.exit()
elif opt in ("-i", "--ifile"):
inputfile = arg
elif opt in ("-o", "--ofile"):
outputfile = arg
print ('Input file is "', inputfile)
print ('Output file is "', outputfile)
if __name__ == "__main__":
main(sys.argv[1:])
運行如下：
$ test.py -h
usage: test.py -i -o
$ test.py -i BMP -o
usage: test.py -i -o
$ test.py -i inputfile -o outputfile
Input file is " inputfile
Output file is " outputfile
10. 變量定義：
vars.py
#!/usr/bin/python3
counter = 100 # An integer assignment
miles = 1000.0 # A floating point
name = "John" # A string
print (counter)
print (miles)
print (name)
11. 對string進行運算：
#!/usr/bin/python3
str = 'Hello World!'
print (str) # Prints complete string
print (str[0]) # Prints first character of the string
print (str[2:5]) # Prints characters starting from 3rd to 5th
print (str[2:]) # Prints string starting from 3rd character
print (str * 2) # Prints string two times
print (str + "TEST") # Prints concatenated string
12. python組件：list（可修改）
提取組件內(nèi)信息：
#!/usr/bin/python3
list = [ 'abcd', 786 , 2.23, 'john', 70.2 ]
tinylist = [123, 'john']
print (list) # Prints complete list
print (list[0]) # Prints first element of the list
print (list[1:3]) # Prints elements starting from 2nd till 3rd
print (list[2:]) # Prints elements starting from 3rd element
print (tinylist * 2) # Prints list two times
print (list + tinylist) # Prints concatenated lists
*為什么給出的答案里面有很多位小數(shù)
13. python組件：tuple（元組）：不可修改
#!/usr/bin/python3
tuple = ( 'abcd', 786 , 2.23, 'john', 70.2 )
tinytuple = (123, 'john')
print (tuple) # Prints complete tuple
print (tuple[0]) # Prints first element of the tuple
print (tuple[1:3]) # Prints elements starting from 2nd till 3rd
print (tuple[2:]) # Prints elements starting from 3rd element
print (tinytuple * 2) # Prints tuple two times
print (tuple + tinytuple) # Prints concatenated tuple
14. python組件：字典（dict）
#!/usr/bin/python3
dict = {}
dict['one'] = "This is one"
dict[2] = "This is two"
tinydict = {'name': 'john','code':6734, 'dept': 'sales'}
print (dict['one']) # Prints value for 'one' key
print (dict[2]) # Prints value for 2 key
print (tinydict) # Prints complete dictionary
print (tinydict.keys()) # Prints all the keys
print (tinydict.values()) # Prints all the values
15. python基本運算：
#!/usr/bin/python3
a = 21
b = 10
c = 0
c = a + b
print ("Line 1 - Value of c is ", c)
c = a - b
print ("Line 2 - Value of c is ", c )
c = a * b
print ("Line 3 - Value of c is ", c)
c = a / b
print ("Line 4 - Value of c is ", c )
c = a % b
print ("Line 5 - Value of c is ", c)
a = 2
b = 3
c = a**b
print ("Line 6 - Value of c is ", c)
a = 10
b = 5
c = a//b
print ("Line 7 - Value of c is ", c)
16. python二元運算（比較等）
#!/usr/bin/python3
a = 21
b = 10
if ( a == b ):
print ("Line 1 - a is equal to b")
else:
print ("Line 1 - a is not equal to b")
if ( a != b ):
print ("Line 2 - a is not equal to b")
else:
print ("Line 2 - a is equal to b")
if ( a < b ):
print ("Line 3 - a is less than b" )
else:
print ("Line 3 - a is not less than b")
if ( a > b ):
print ("Line 4 - a is greater than b")
else:
print ("Line 4 - a is not greater than b")
a,b=b,a #values of a and b swapped. a becomes 10, b becomes 21
if ( a <= b ):
print ("Line 5 - a is either less than or equal to b")
else:
print ("Line 5 - a is neither less than nor equal to b")
if ( b >= a ):
print ("Line 6 - b is either greater than or equal to b")
else:
print ("Line 6 - b is neither greater than nor equal to b")
17. 其他運算：
#!/usr/bin/python3
a = 21
b = 10
c = 0
c = a + b
print ("Line 1 - Value of c is ", c)
c += a
print ("Line 2 - Value of c is ", c )
c *= a
print ("Line 3 - Value of c is ", c )
c /= a
print ("Line 4 - Value of c is ", c )
c = 2
c %= a
print ("Line 5 - Value of c is ", c)
c **= a
print ("Line 6 - Value of c is ", c)
c //= a
print ("Line 7 - Value of c is ", c)
*其中：%是取余數(shù)運算镣衡；**是求冪次方運算，//是返回商的整數(shù)部分
18. 對數(shù)字背后8位碼的運算：
#!/usr/bin/python3
a = 60 # 60 = 0011 1100
b = 13 # 13 = 0000 1101
print ('a=',a,':',bin(a),'b=',b,':',bin(b))
c = 0
c = a & b; # 12 = 0000 1100
print ("result of AND is ", c,':',bin(c))
c = a | b; # 61 = 0011 1101
print ("result of OR is ", c,':',bin(c))
c = a ^ b; # 49 = 0011 0001
print ("result of EXOR is ", c,':',bin(c))
c = ~a; # -61 = 1100 0011
print ("result of COMPLEMENT is ", c,':',bin(c))
c = a << 2; # 240 = 1111 0000
print ("result of LEFT SHIFT is ", c,':',bin(c))
c = a >> 2; # 15 = 0000 1111
print ("result of RIGHT SHIFT is ", c,':',bin(c))
比特位運算符：
& Binary AND Operator copies a bit to the result, if it exists in both operands(a & b) (means 0000 1100)
| Binary OR It copies a bit, if it exists in either operand.(a | b) = 61 (means 0011 1101)
^ Binary XOR It copies the bit, if it is set in one operand but not both.(a ^ b) = 49 (means 0011 0001)
~ Binary Ones ComplementIt is unary and has the effect of 'flipping' bits.(~a ) = -61 (means 1100 0011 in 2's complement form due to a signed binary number.
<< Binary Left Shift The left operand’s value is moved left by the number of bits specified by the right operand.a << = 240 (means 1111 0000)
>> Binary Right Shift The left operand’s value is moved right by the number of bits specified by the right operand.a >> = 15 (means 0000 1111)
19. in和notin運算符：
#!/usr/bin/python3
a = 10
b = 20
list = [1, 2, 3, 4, 5 ]
if ( a in list ):
print ("Line 1 - a is available in the given list")
else:
print ("Line 1 - a is not available in the given list")
if ( b not in list ):
print ("Line 2 - b is not available in the given list")
else:
print ("Line 2 - b is available in the given list")
c=b/a
if ( c in list ):
print ("Line 3 - a is available in the given list")
else:
print ("Line 3 - a is not available in the given list")
20. is和isnot運算符
#!/usr/bin/python3
a = 20
b = 20
print ('Line 1','a=',a,':',id(a), 'b=',b,':',id(b))
if ( a is b ):
print ("Line 2 - a and b have same identity")
else:
print ("Line 2 - a and b do not have same identity")
if ( id(a) == id(b) ):
print ("Line 3 - a and b have same identity")
else:
print ("Line 3 - a and b do not have same identity")
b = 30
print ('Line 4','a=',a,':',id(a), 'b=',b,':',id(b))
if ( a is not b ):
print ("Line 5 - a and b do not have same identity")
else:
print ("Line 5 - a and b have same identity")
21. 運算符優(yōu)先級的例子：
#!/usr/bin/python3
a = 20
b = 10
c = 15
d = 5
print ("a:%d b:%d c:%d d:%d" % (a,b,c,d ))
e = (a + b) * c / d #( 30 * 15 ) / 5
print ("Value of (a + b) * c / d is ", e)
e = ((a + b) * c) / d # (30 * 15 ) / 5
print ("Value of ((a + b) * c) / d is ", e)
e = (a + b) * (c / d) # (30) * (15/5)
print ("Value of (a + b) * (c / d) is ", e)
e = a + (b * c) / d # 20 + (150/5)
print ("Value of a + (b * c) / d is ", e)
22. if語句：
#!/usr/bin/python3
var1 = 100
if var1:
print ("1 - Got a true expression value")
print (var1)
var2 = 0
if var2:
print ("2 - Got a true expression value")
print (var2)
print ("Good bye!")
23. if-else-循環(huán)
#!/usr/bin/python3
amount=int(input("Enter amount: "))
if amount<1000:
discount=amount*0.05
print ("Discount",discount)
else:
discount=amount*0.10
print ("Discount",discount)
print ("Net payable:",amount-discount)
24. elseif語句：elif
#!/usr/bin/python3
amount=int(input("Enter amount: "))
if amount<1000:
discount=amount*0.05
print ("Discount",discount)
elif amount<5000:
discount=amount*0.10
print ("Discount",discount)
else:
discount=amount*0.15
print ("Discount",discount)
("Net payable:",amount-discount)
25. 嵌套if-else：
# !/usr/bin/python3
num=int(input("enter number"))
if num%2==0:
if num%3==0:
print ("Divisible by 3 and 2")
else:
print ("divisible by 2 not divisible by 3")
else:
if num%3==0:
print ("divisible by 3 not divisible by 2")
else:
print ("not Divisible by 2 not divisible by 3")
26. if語句結(jié)果只有一行--可以寫在同一行
#!/usr/bin/python3
var = 100
if ( var == 100 ) : print ("Value of expression is 100")
print ("Good bye!")
27. while循環(huán)：
#!/usr/bin/python3
var = 1
while var == 1 : # This constructs an infinite loop
num = int(input("Enter a number :"))
print ("You entered: ", num)
print ("Good bye!")
28. 在while循環(huán)里添加else跳出：
#!/usr/bin/python3
count = 0
while count < 5:
print (count, " is less than 5")
count = count + 1
else:
print (count, " is not less than 5")
29. range函數(shù)：
a = range(5)
print(a)
a=list(range(5))
print(a)
for var in list(range(5)): print (var)
30. for循環(huán)：
#!/usr/bin/python3
for letter in 'Python': # traversal of a string sequence
print ('Current Letter :', letter)
print()
fruits= ['banana', 'apple', 'mango']
for fruit in fruits: # traversal of List sequence
print ('Current fruit :', fruit)
print ("Good bye!")
31. 利用index遍歷：
#!/usr/bin/python3
fruits = ['banana', 'apple', 'mango']
for index in range(len(fruits)):
print ('Current fruit :', fruits[index])
print ("Good bye!")
32. 在for循環(huán)中插入if-else判定：
#!/usr/bin/python3
numbers=[11,33,55,39,55,75,37,21,23,41,13]
for num in numbers:
if num%2==0:
print ('the list contains an even number')
break
else:
print ('the list doesnot contain even number')
33. 嵌套循環(huán)：
遍歷10-10乘法表
#!/usr/bin/python3
import sys
for i in range(1,11):
for j in range(1,11):
k=i*j
print (k, end=' ')
print()
為什么是1-11：
34. 利用break跳出循環(huán)：
#!/usr/bin/python3
for letter in 'Python': # First Example
if letter == 'h':
break
print ('Current Letter :', letter)
var = 10 # Second Example
while var > 0:
print ('Current variable value :', var)
var = var -1
if var == 5:
break
print ("Good bye!")
35. 利用for-else跳出循環(huán)
#!/usr/bin/python3
no=int(input('any number: '))
numbers=[11,33,55,39,55,75,37,21,23,41,13]
for num in numbers:
if num==no:
print ('number found in list')
break
else:
print ('number not found in list')
36. continue語句：
#!/usr/bin/python3
for letter in 'Python': # First Example
if letter == 'h':
continue
print ('Current Letter :', letter)
var = 10 # Second Example
while var > 0:
var = var -1
if var == 5:
continue
print ('Current variable value :', var)
print ("Good bye!")
37. ceil（）：向上取整
#!/usr/bin/python3
import math # This will import math module
print ("math.ceil(-45.17) : ", math.ceil(-45.17))
print ("math.ceil(100.12) : ", math.ceil(100.12))
print ("math.ceil(100.72) : ", math.ceil(100.72))
print ("math.ceil(math.pi) : ", math.ceil(math.pi))
38. exp（）：指數(shù)次方
#!/usr/bin/python3
import math # This will import math module
print ("math.exp(-45.17) : ", math.exp(-45.17))
print ("math.exp(100.12) : ", math.exp(100.12))
print ("math.exp(100.72) : ", math.exp(100.72))
print ("math.exp(math.pi) : ", math.exp(math.pi))
39. fabs（）：絕對值
#!/usr/bin/python3
import math # This will import math module
print ("math.fabs(-45.17) : ", math.fabs(-45.17))
print ("math.fabs(100.12) : ", math.fabs(100.12))
print ("math.fabs(100.72) : ", math.fabs(100.72))
print ("math.fabs(math
.pi) : ", math.fabs(math.pi))
40. floor（）：向下取整
#!/usr/bin/python3
import math # This will import math module
print ("math.floor(-45.17) : ", math.floor(-45.17))
print ("math.floor(100.12) : ", math.floor(100.12))
print ("math.floor(100.72) : ", math.floor(100.72))
print ("math.floor(math.pi) : ", math.floor(math.pi))
42.獲取字符串中的信息：
#!/usr/bin/python3
var1 = 'Hello World!'
var2 = "Python Programming"
print ("var1[0]: ", var1[0])
print ("var2[1:5]: ", var2[1:5])
43. 對字符串進行修改：
#!/usr/bin/python3
var1 = 'Hello World!'
print ("Updated String :- ", var1[:6] + 'Python')
44. 字符串格式化嗤放？
#!/usr/bin/python3
var1 = 'Hello World!'
print ("Updated String :- ", var1[:6] + 'Python')
45. 三引號：
可以保留格式思喊？
#!/usr/bin/python3
para_str = """this is a long string that is made up of
several lines and non-printable characters such as
TAB ( \t ) and they will show up that way when displayed.
NEWLINEs within the string, whether explicitly given like
this within the brackets [ \n ], or just a NEWLINE within
the variable assignment will also show up.
"""
print (para_str)
46. raw-string：功能存疑
#!/usr/bin/python3
print ('C:\\nowhere')
print (r'C:\\nowhere')
47. capitalize（）：首字母大寫
#!/usr/bin/python3
str = "this is string example....wow!!!"
print ("str.capitalize() : ", str.capitalize())
48. 訪問list里的值：
#!/usr/bin/python3
list1 = ['physics', 'chemistry', 1997, 2000]
list2 = [1, 2, 3, 4, 5, 6, 7 ]
print ("list1[0]: ", list1[0])
print ("list2[1:5]: ", list2[1:5])
49. 修改list：
#!/usr/bin/python3
list1 = ['physics', 'chemistry', 1997, 2000]
list2 = [1, 2, 3, 4, 5, 6, 7 ]
print ("list1[0]: ", list1[0])
print ("list2[1:5]: ", list2[1:5])
50. 刪除list：”
#!/usr/bin/python3
list = ['physics', 'chemistry', 1997, 2000]
print (list)
del list[2]
print ("After deleting value at index 2 : ", list)
51. max（）：返回最大值（首字母/數(shù)字）
#!/usr/bin/python3
list1, list2 = ['C++','Java', 'Python'], [456, 700, 200]
print ("Max value element : ", max(list1))
print ("Max value element : ", max(list2))
52.list（）：把tuple轉(zhuǎn)化為list
#!/usr/bin/python3
aTuple = (123, 'C++', 'Java', 'Python')
list1 = list(aTuple)
print ("List elements : ", list1)
str="Hello World"
list2=list(str)
print ("List elements : ", list2)
53. append：向list里添加元素
#!/usr/bin/python3
list1 = ['C++', 'Java', 'Python']
list1.append('C#')
print ("updated list : ", list1)
54. count（）：對list里的目標元素計數(shù)
#!/usr/bin/python3
aList = [123, 'xyz', 'zara', 'abc', 123];
print ("Count for 123 : ", aList.count(123))
print ("Count for zara : ", aList.count('zara'))
55. pop（）：從list中剔除/什么方式里面的元素？
#!/usr/bin/python3
list1 = ['physics', 'Biology', 'chemistry', 'maths']
list1.pop()
print ("list now : ", list1)
list1.pop(1)
print ("list now : ", list1)
56. remove（）：從list里刪除指定元素
#!/usr/bin/python3
list1 = ['physics', 'Biology', 'chemistry', 'maths']
list1.remove('Biology')
print ("list now : ", list1)
list1.remove('maths')
print ("list now : ", list1)
57. reverse（）：對list內(nèi)順序進行顛倒
#!/usr/bin/python3
list1 = ['physics', 'Biology', 'chemistry', 'maths']
list1.reverse()
print ("list now : ", list1)
58. sort（）：對list里元素排序
#!/usr/bin/python3
list1 = ['physics', 'Biology', 'chemistry', 'maths']
list1.sort()
print ("list now : ", list1)
59. 調(diào)用tuple里的信息
#!/usr/bin/python3
tup1 = ('physics', 'chemistry', 1997, 2000)
tup2 = (1, 2, 3, 4, 5, 6, 7 )
print ("tup1[0]: ", tup1[0])
print ("tup2[1:5]: ", tup2[1:5])
60. tuple不能修改次酌，但可以調(diào)用現(xiàn)有的tuple注入到新的tuple里進行類似修改的重新賦值：
#!/usr/bin/python3
tup1 = (12, 34.56)
tup2 = ('abc', 'xyz')
# Following action is not valid for tuples
# tup1[0] = 100;
# So let's create a new tuple as follows
tup3 = tup1 + tup2
print (tup3)
61. len（）： 對tuple進行計數(shù)
#!/usr/bin/python3
tuple1, tuple2 = (123, 'xyz', 'zara'), (456, 'abc')
print ("First tuple length : ", len(tuple1))
print ("Second tuple length : ", len(tuple2))
62. max（）：返回數(shù)組中的最大值
#!/usr/bin/python3
tuple1, tuple2 = ('maths', 'che', 'phy', 'bio'), (456, 700, 200)
print ("Max value element : ", max(tuple1))
print ("Max value element : ", max(tuple2))
63. tuple（）：把list轉(zhuǎn)化為tuple
#!/usr/bin/python3
list1= ['maths', 'che', 'phy', 'bio']
tuple1=tuple(list1)
print ("tuple elements : ", tuple1)
64. 對字典里的數(shù)進行訪問
#!/usr/bin/python3
dict = {'Name': 'Zara', 'Age': 7, 'Class': 'First'}
print ("dict['Name']: ", dict['Name'])
print ("dict['Age']: ", dict['Age'])
65. 更新dict里的內(nèi)容
#!/usr/bin/python3
dict = {'Name': 'Zara', 'Age': 7, 'Class': 'First'}
dict['Age'] = 8; # update existing entry
dict['School'] = "DPS School" # Add new entry
print ("dict['Age']: ", dict['Age'])
print ("dict['School']: ", dict['School'])
66. 刪除字典里的信息
#!/usr/bin/python3
dict = {'Name': 'Zara', 'Age': 7, 'Class': 'First'}
del dict['Name'] # remove entry with key 'Name'
dict.clear() # remove all entries in dict
del dict # delete entire dictionary
print ("dict['Age']: ", dict['Age'])
print ("dict['School']: ", dict['School'])
67. dict內(nèi)容沒有限制：
#!/usr/bin/python3
dict = {'Name': 'Zara', 'Age': 7, 'Name': 'Manni'}
print ("dict['Name']: ", dict['Name'])
68. str（）：把字典字符化
#!/usr/bin/python3
dict = {'Name': 'Manni', 'Age': 7, 'Class': 'First'}
print ("Equivalent String : %s" % str (dict))
69. type（）返回字典內(nèi)的數(shù)據(jù)類型：
#!/usr/bin/python3
dict = {'Name': 'Manni', 'Age': 7, 'Class': 'First'}
print ("Variable Type : %s" % type (dict))
70. clear（）清空字典
dict = {'Name': 'Zara', 'Age': 7}
print ("Start Len : %d" % len(dict))
dict.clear()
print ("End Len : %d" % len(dict))
71. copy（）從字典中copy信息：
#!/usr/bin/python3
dict1 = {'Name': 'Manni', 'Age': 7, 'Class': 'First'}
dict2 = dict1.copy()
print ("New Dictionary : ",dict2)
72. fromkeys（）從原字典中拿出值和類型構(gòu)成一個新字典
#!/usr/bin/python3
seq = ('name', 'age', 'sex')
dict = dict.fromkeys(seq)
print ("New Dictionary : %s" % str(dict))
dict = dict.fromkeys(seq, 10)
print ("New Dictionary : %s" % str(dict))
73. items（）返回（key value）類型
#!/usr/bin/python
dict = {'Name': 'Zara', 'Age': 7}
print ("Value : %s" % dict.items())
74. keys（）返回（字典里所有的0key）
#!/usr/bin/python3
dict = {'Name': 'Zara', 'Age': 7}
print ("Value : %s" % dict.keys())
75.?setdefault（）方法類似于get（）
#!/usr/bin/python3
dict = {'Name': 'Zara', 'Age': 7}
print ("Value : %s" % dict.setdefault('Age', None))
print ("Value : %s" % dict.setdefault('Sex', None))
print (dict)
76. tick（）好像是獲得時間的函數(shù)（不確定）
#!/usr/bin/python3
import time; # This is required to include time module.
ticks = time.time()
print ("Number of ticks since 12:00am, January 1, 1970:", ticks)
時間間隔是以秒為單位的浮點數(shù)恨课。 從1970年1月1日上午12:00(epoch)，這是一種時間的特殊時刻表示岳服。
在Python中剂公，當前時刻與上述特殊的某個時間點之間以秒為單位的時間。這個時間段叫做Ticks吊宋。
77. clock（）時鐘函數(shù)
#!/usr/bin/python3
import time
def procedure():
time.sleep(2.5)
# measure process time
t0 = time.clock()
procedure()
print (time.clock() - t0, "seconds process time")
# measure wall time
t0 = time.time()
procedure()
print (time.time() - t0, "seconds wall time")
Python time clock() 函數(shù)以浮點數(shù)計算的秒數(shù)返回當前的CPU時間纲辽。用來衡量不同程序的耗時，比time.time()更有用璃搜。
這個需要注意拖吼，在不同的系統(tǒng)上含義不同。在UNIX系統(tǒng)上这吻，它返回的是"進程時間"绿贞，它是用秒表示的浮點數(shù)（時間戳）。而在WINDOWS中橘原，第一次調(diào)用，返回的是進程運行的實際時間涡上。而第二次之后的調(diào)用是自第一次調(diào)用以后到現(xiàn)在的運行時間趾断。（實際上是以WIN32上QueryPerformanceCounter()為基礎(chǔ)，它比毫秒表示更為精確）
78.?如何定義函數(shù)
#!/usr/bin/python3
# Function definition is here
def printme( str ):
"This prints a passed string into this function"
print (str)
return
# Now you can call printme function
printme("This is first call to the user defined function!")
printme("Again second call to the same function")
79. 參數(shù)通過reference傳遞
#!/usr/bin/python3
# Function definition is here
def changeme( mylist ):
"This changes a passed list into this function"
print ("Values inside the function before change: ", mylist)
mylist[2]=50
print ("Values inside the function after change: ", mylist)
return
# Now you can call changeme function
mylist = [10,20,30]
changeme( mylist )
print ("Values outside the function: ", mylist)
80. 例子2
#!/usr/bin/python3
# Function definition is here
def changeme( mylist ):
"This changes a passed list into this function"
mylist = [1,2,3,4] # This would assi new reference in mylist
print ("Values inside the function: ", mylist)
return
# Now you can call changeme function
mylist = [10,20,30]
changeme( mylist )
print ("Values outside the function: ", mylist)
81. 函數(shù)外給參數(shù)賦值：
#!/usr/bin/python3
# Function definition is here
def printinfo( name, age ):
"This prints a passed info into this function"
print ("Name: ", name)
print ("Age ", age)
return
# Now you can call printinfo function
printinfo( age=50, name="miki" )
82.默認給參數(shù)賦值：
?#!/usr/bin/python3
# Function definition is here
def printinfo( name, age = 35 ):
"This prints a passed info into this function"
print ("Name: ", name)
print ("Age ", age)
return
# Now you can call printinfo function
printinfo( age=50, name="miki" )
printinfo( name="miki" )
83. 針對asterisk吩愧？的賦值和調(diào)用
#!/usr/bin/python3
# Function definition is here
def printinfo( arg1, *vartuple ):
"This prints a variable passed arguments"
print ("Output is: ")
print (arg1)
for var in vartuple:
print (var)
return
# Now you can call printinfo function
printinfo( 10 )
printinfo( 70, 60, 50 )
84. lambda：
ambda 定義了一個匿名函數(shù)
lambda 并不會帶來程序運行效率的提高芋酌，只會使代碼更簡潔。
如果可以使用for...in...if來完成的雁佳，堅決不用lambda脐帝。
如果使用lambda，lambda內(nèi)不要包含循環(huán)糖权，如果有堵腹，我寧愿定義函數(shù)來完成，使代碼獲得可重用性和更好的可讀性星澳。
總結(jié)：lambda 是為了減少單行函數(shù)的定義而存在的疚顷。
#!/usr/bin/python3
# Function definition is here
sum = lambda arg1, arg2: arg1 + arg2
# Now you can call sum as a function
print ("Value of total : ", sum( 10, 20 ))
print ("Value of total : ", sum( 20, 20 ))
85. return語句：
#!/usr/bin/python3
# Function definition is here
def sum( arg1, arg2 ):
# Add both the parameters and return them."
total = arg1 + arg2
print ("Inside the function : ", total)
return total
# Now you can call sum function
total = sum( 10, 20 )
print ("Outside the function : ", total )
86. global和local變量的區(qū)別
#!/usr/bin/python3
total = 0 # This is global variable.
# Function definition is here
def sum( arg1, arg2 ):
# Add both the parameters and return them."
total = arg1 + arg2; # Here total is local variable.
print ("Inside the function local total : ", total)
return total
# Now you can call sum function
sum( 10, 20 )
print ("Outside the function global total : ", total )
87. module：規(guī)范的程序塊
def print_func( par ):
? ? print ("Hello : ", par)
? ? return
88. import關(guān)鍵字：
#!/usr/bin/python3
# Import module support
import support
# Now you can call defined function that module as follows
support.print_func("Zara")
89. 另一種斐波那契數(shù)列的寫法：
#!/usr/bin/python3
# Fibonacci numbers module
def fib(n): # return Fibonacci series up to n
result = []
a, b = 0, 1
while b < n:
result.append(b)
a, b = b, a+b
return result
>>> from fib import fib
>>> fib(100)
90. dir用法：
#!/usr/bin/python3
# Import built-in module math
import math
content = dir(math)
print (content)
91. 打開文件：
#!/usr/bin/python3
# Open a file
fo = open("foo.txt", "wb")
print ("Name of the file: ", fo.name)
print ("Closed or not : ", fo.closed)
print ("Opening mode : ", fo.mode)
fo.close()
92. write-file方法
#!/usr/bin/python3
# Open a file
fo = open("foo.txt", "w")
fo.write( "Python is a great language.\nYeah its great!!\n")
# Close opend file
fo.close()
93. read-file方法
#!/usr/bin/python3
# Open a file
fo = open("foo.txt", "r+")
str = fo.read(10)
print ("Read String is : ", str)
# Close opened file
fo.close()
94. tell（）查詢文件位置
# Open a file
fo = open("foo.txt", "r+")
str = fo.read(10)
print ("Read String is : ", str)
# Check current position
position = fo.tell()
print ("Current file position : ", position)
# Reposition pointer at the beginning once again
position = fo.seek(0, 0)
str = fo.read(10)
print ("Again read String is : ", str)
# Close opened file
fo.close()
95. fileno（）方法--
#!/usr/bin/python3
# Open a file
fo = open("foo.txt", "wb")
print ("Name of the file: ", fo.name)
fid = fo.fileno()
print ("File Descriptor: ", fid)
# Close opend file
fo.close()
96. isatty（）：如果文件連接(與終端設(shè)備相關(guān)聯(lián))到tty(類似)設(shè)備，則此方法返回true，否則返回false腿堤。
#!/usr/bin/python3
# Open a file
fo = open("foo.txt", "wb")
print ("Name of the file: ", fo.name)
ret = fo.isatty()
print ("Return value : ", ret)
# Close opend file
fo.close()
97. next（）
#!/usr/bin/python3
# Open a file
fo = open("foo.txt", "r")
print ("Name of the file: ", fo.name)
for index in range(5):
line = next(fo)
print ("Line No %d - %s" % (index, line))
# Close opened file
fo.close()
98. readline函數(shù)
#!/usr/bin/python3
# Open a file
fo = open("foo.txt", "r+")
print ("Name of the file: ", fo.name)
line = fo.read(10)
print ("Read Line: %s" % (line))
# Close opened file
fo.close()
99. 另一個readline函數(shù)：
#!/usr/bin/python3
# Open a file
fo = open("foo.txt", "r+")
print ("Name of the file: ", fo.name)
line = fo.readline()
print ("Read Line: %s" % (line))
line = fo.readline(5)
print ("Read Line: %s" % (line))
# Close opened file
fo.close()
100. 令另一個readline函數(shù)：
#!/usr/bin/python3
# Open a file
fo = open("foo.txt", "r+")
print ("Name of the file: ", fo.name)
line = fo.readlines()
print ("Read Line: %s" % (line))
line = fo.readlines(2)
print ("Read Line: %s" % (line))
# Close opened file
fo.close()
101. access方法：
#!/usr/bin/python3
import os, sys
# Assuming /tmp/foo.txt exists and has read/write permissions.
ret = os.access("/tmp/foo.txt", os.F_OK)
print ("F_OK - return value %s"% ret)
ret = os.access("/tmp/foo.txt", os.R_OK)
print ("R_OK - return value %s"% ret)
102.?
