Python Foundation Day4

Overall outline
One
1,int. Number: operation. 1, 2,3 ...
2,bool. true: false.
3,str. Simple and small amount of storage data, and the corresponding operation name = ' Alex ',
4,tupe. (1, ' Alex ')

5,list: Large amount of data, [1, ' ses ', true,[1,2,3],{' name ': ' Jinxin '}]

6,dict: Dictionary {' name ': ' Jinxin ', ' age ':, ' name_list ': [' Zhang San ', ' John Doe ']}

1,  about the conversion of bool and STR

bool: True True 1, false false 0

 1 String--->bool value bool (str)

non-empty string converted to bool True
' empty string converted to bool False '
Example
s = ' Sdfa '
S1 = ' a '
s2 = ' 1 '
s3 = ' '
Print (bool (s))
Print (bool (S1))
print (bool (s2))
Print (bool (S3))

#bool--->str value

Cases
A = str (true) # ' true '
A1 = str (2 > 1) # ' True '
Print (A1,type (A1)) ' True '

b = str (false) # ' false '

Print (A,type (a))

Print (B,type (b))


Because the null is False
Name = ' '
If Name:
     Print (' input correct ')
Else
     Print (' Please enter content ')

2. Index and slice [start position: End Position: Step]
Example

1, index and slice [start position: End Position: Step]
S1 = ' python full stack phase 8 '
Index starting from 0 [index (subscript, index)]
# print (s1[0])  p
# print (s1[3])  h
# print (s1[5])  n
# print (s1[6])  full
# print (S1[-1]) period

#切片 Gu Tou Disregard butt  Note 1 6th no actual to 5th   2 would have 9 characters but 10 12 19 end up so default to the last 3  
# print (S1[0:6])   
# print (S1[6:10])

Full Stack 8 issue

#pto
Take the piece

[Start Position: End Position: Step]

#s1 = ' python full stack 8 '
# print (S1[0:5:2])  
# print (S1[0:7:3])  ph full

#倒取值: Add step  3::1 and 3::-1 difference     3::1 print hon full stack phase 8    3::-1  

# print (S1[3::-1])

# print (S1) #不变
# s2 = S1[0:6]
# Print (S2)
Python


3 String about uppercase lowercase
ret = ' Alexs '
#字符串的使用方法.
#1 Capitalize first letter, other all lowercase    str1
Print (STR,STR1)  fixed usage

ret = "Wangyan"
Ret1 = "Wangyan". Capitalize ()
Print (RET,RET1)

C

Example all uppercase or full lowercase
ret = ' Wangyan '
Ret2 = Ret.upper ()
Ret3 = Ret.lower ()
Print (RET2,RET3)


Code = ' A '
Your_code = input (' Enter verification code, case insensitive ')
if Your_code = = ' a ' or your_code = = ' A ':
    Print (' you entered the correct ')
Else:print (' Please re-enter ')

Case-insensitive usage

Code = ' Wangyan '. Lower ()
Your_code = input (' Enter a case-insensitive letter '). Lower ()
if code = = Your_code:
    Print (' correct it ')
else:
    Print (' re-enter ')

Code = ' Adee '. Upper ()
Your_code = input (' Please enter a verification code, not case sensitive '). Upper ()
if Your_code = = Code:
    Print (' you entered the correct ')
Else:print (' Please re-enter ')
‘‘‘
# case Flip  . Swapcase ()

Example
Code = ' Wangyan '
Code1 = Code.swapcase ()
Print (CODE,CODE1)

Wangyan Wangyan

#以特殊符号或者空格隔开, the first letter of each string is capitalized title ()
Example

Code = ' Wangyan '

Print (Code.title ())
Wangyan

  Fixed format      string. Center (number is the space between the center of the string and the ' fill content ')

Code = ' Wangyan '
Print (Code.center, ' @ '     ) @@@@@@@@@@@@@[email protected]@@@@@@@@@@@@

# * returns BOOL value  StartsWith endswith

Code = ' Wangyan '
Code1 = Code.startswith (' W ')

True as long as the first one or a few are false otherwise

ret = ' 123454 '
Ret2 = Ret.endswith (' 3 ', 0, 3)
Print (Ret2)

   ret = "Alex"
# Ret5 = Ret.startswith (' l ', 1,3)  # Slice
# Print (RET5)
True
# Ret6 = Ret.endswith (' S ',-2,)
# Print (RET6)
False

# * * Number of Count letters

Example
ret = ' Wangyanluodan '
Ret6 = Ret.count (' A ', 0,6)
Print (RET6)
2 x

ret = Alex
# ret7 = Ret22.count (' a ')
# ret7 = Ret22.count (' ale ')  # whole vs. individual
# ret7 = Ret22.count (' W ')  # 0
# ret7 = Ret22.count (' A ', 0,7)  # Slice of Count
# Print (RET7)

TAB key Completion
# a2 = "Qwaaaaaaaa\taa"
#\ t in front of the completion
# By default, a tab key becomes 4 spaces, if the character in front of the tab is less than 8, then complete 8, if the character in front of the TAB key is more than 8 less than 16, then complete 16, and so on each complement of 8 .
# ret8 = A2.expandtabs ()
# Print (Ret8,len (RET8))
Example

a1= "Qwaaaaaaaa\taa"
A2 = A1.expandtabs ()
Print (A2)

Find and Index lookups
ret = ' Aleaxs '
# * Find Index by element (find first element), cannot find return-1
# ret9 = Ret.find (' a ')
# # RET9 = Ret.find (' W ', 0,5)
# Print (RET9)
#index and find use the same, the element can not be found, will be error
# ret10 = Ret.index (' W ')
# Print (ret10)

a1= "Qwaaaaaaaa\taa"

A2 = A1.find (' B ')
Print (A2)  -1
‘‘‘
a1= "Qwaaaaaaaa\taa"

A2 = A1.find (' a ')
Print (A2) 2

a1= "Qwaaaaaaaa\taa"

A2 = A1.index (' a ')
Print (A2) 2

a1= "Qwaaaaaaaa\taa"

A2 = A1.index (' W ')
Print (A2) error

#* Strip Remove the space before and after the string and the element you want to remove

Ret
# ret11 = ' Alex '. Strip ()
# Print (ret11)
‘‘‘
name = ' Alex '
Username = input (' Please enter your user name: '). Strip ()
If username = = Name:
Print (' Login successful ')
‘‘‘
# ret11 = ' Alex '. Lstrip ()
# Print (ret11)
# ret11 = ' Alex '. Rstrip ()
# Print (ret11)
#一:
# ret12 = ' Asldfkjafa '. Strip (' a ')
# Print (ret12)
#二:
# ret13 = ' Asldfkjafa '. Strip (' sa ')
# Print (ret13)
# ret13 = ' Asldfkjafa '. Strip (' Salf ')
# Print (ret13)
# ret14 = ' Asldfkajafa '. Strip (' Sawlf ')
# Print (ret14)

#split * Splitting a string into a list
# ret15 = ' jinxin Alex Wusir '
# ret16 = Ret15.split ()
# Print (ret16)
# ret15 = ' Jinxin,alex,wusir '
# ret16 = Ret15.split (', ')
# Print (ret16)
# ret15 = ' title Tle tlie '
# ret16 = ret15.split (' t ')
# Print (ret16)
# * Replaces replace
# ret18 = ' Pink turned on pink-grade third pink '
# ret19 = ret18.replace (' Pink ', ' Tender Green ', 1)
# Print (ret19)

# Formatted output format
#第一种:
# ret20 = ' name:{},sex:{}, Height: {} '. Format (' Alex ', ' Ladyboy ', 178)
# Print (ret20)
#第二种:
# ret20 = ' Name:{0},sex:{1}, Height: {2},name:{0} '. Format (' Alex ', ' Ladyboy ', 178)
# Print (ret20)
#第三种: Key-value pairs
# ret20 = ' Name:{name},sex:{sex}, Height: {high},name:{name} ' \
#. Format (sex = ' ladyboy ', high = 178,name= ' Alex ')
# Print (ret20)

# Judging conditions
# name= ' 123 '
# Print (Name.isalnum ()) #字符串由字母或数字组成
# Print (Name.isalpha ()) #字符串只由字母组成
# Print (Name.isdigit ()) #字符串只由数字组成


s = ' AELSDSKJL '
# s = s[1:]
# print (s)

# print (len (s)) #测量长度
# index = 0
# while True:
# print (S[index])
# index + = 1
# if Index = = Len (s): Break
#for variable in to iterate over an object
# for I in S:
# Print (i)
s = ' FS4DKJLA123FKJ2DSA '
Count = 0

For I in S:
If I.isdigit ():
Count + = 1
Else:print (666)
Print (count)

Python Foundation Day4