learning python string dictionary --- common method ---- ---- tuple basic file operations

Dictionary # 
# by key: value data storage mode 
# key value through the high efficiency 
info [ 'name'] 
# modify the original value 
info.setdefault ( 'name', 'LDH') 
# does not change the original data 
# modify 
info [ 'name'] = 'value' 

# remove 
info.pop ( 'Key') 
del info [ 'Key'] 
info.popitem () to delete a random data # 

# check 
info.get ( 'Key') 
info .get ( 'key', 'default') 
# key if the key corresponding to the presence of the return value 
# default value if the key does not exist is returned 
info [ 'key'] 

info.keys () 
# Get all dictionary key 
info .values () 
# get all values dictionary 
info.clear () 
info.update (info1) # dictionary combined 
# info1 be added to the info 
key in info 
# determines whether the info key is present in the 

conventional method # string 
str.Strip () 
# remove both sides of the spaces and line breaks string 
# can not be removed in the middle of the string
str.rstrip () 
# remove line breaks and spaces to the right of the string 
str.lstrip () 
# remove the string to the left of spaces and line breaks 
str.replace ( "", "") 
# replacement string content 
str.index ( 'a') 
# Find a subscript 
str.count ( 'KA') 
# number of characters that appear 
str.find ( 'a') 
# Find subscript 
str.startswith ( '') 
# xxx beginning has been to determine whether 
str. endsWith ( '') 
# xxx has been determined whether the end 
str.upper () 
# becomes all the uppercase letters 
str.lower () 
# all lowercase letters are changed 
str.isdigit () 
# determines whether an integer 
str.capitalize ( ) 
# capitalized 
str.center (50, '=') 
# total length of 50 
# if insufficient length to both sides of the padded number = 
str.zfill (2) 
# 0 up in front of the character 
str.isupper () 
# determines whether all capital letters 
str.islower () 
# determine whether all lowercase
str.isialpha () 
# if not letters or characters 
# full return to true 
str.isalnum () 
# only numbers or letters or characters will not return to true 
# else return false 
str.format () 
# string formatting 

str = 'today is {}, {} welcome log ' 
str.fromat (' a ',' B ') 

str.split (' strings separated ') 
# delimited string 
' specified string '.join (list) 
# inside of the list each element is connected by a specified string up 
s4 = 'insert into stu (id , username, passwd, phone, addr, qq, email, score) value ( "{id}", "{username}", "{password } "," {} Phone "," addr {} "," {} QQ "," In Email {} "," {} Score ") ' 
s4.format (username =' AAA ',. 1 ID = ????? ·····) 
s4.format_map ({ 'username': 'ddd', 'ID':········· 234}) 

# tuple 
# tuple is a list, and can not be modified 
# read only 
T = (. 1, 2,. 3,. 4,. 5) 
T [0] 
# value 
t. count ( "xxx")
# Get the number xxx appearing in the tuple 
t.index ( "value") 
# Get subscript 

- - 
Import the pprint 

# complete print format data type 

# file operation 
# 1, the document reading 
Open () 
# open file three modes 
# read 
f = open (r 'file path', encoding = 'GBK') 
Result reached, f.read = () 
Print (Result) 
f.close () 
# can only be read but not written 

# written 
f = open ( 'file path ',' w ', encoding =' GBK ') 
f.write (' 123456 ') 
f.close () 
# can only write can not read, the contents will be covered before each write, the file does not exist will be created 

# append 
f = open ( 'file path', 'A', encoding = 'GBK') 
f.write ( '7890') 
f.close () 
# can only write can not read, appended to the original file contents later, the file will be created does not exist 

# reading write mode 
# r + r is about as long as the open file does not exist are given 
f = open ( 'C:\\Users\\LDH\\Desktop\\123.txt','r+',encoding='gbk')
f.write ( 'ABC') 
Result reached, f.read = () 
Print (Result) 
f.close () 

# write-read mode 
# w + w is about as long, will overwrite the contents of the source file 
f = open ( 'C: the Users of LDH \\ Desktop \\ \\ \\ 123.txt ',' W + ', encoding =' GBK ') 
f.write (' RTY ') 
Result reached, f.read = () 
Print (Result) 
f.close () 

# a + created file does not exist, the contents of the file append 

F = Open ( 'C: \\ the Users of LDH \\ \\ \\ 123.txt Desktop', '+ A', encoding = 'GBK') 
F. Write ( 'UIO') 
Result reached, f.read = () 
Print (Result) 
f.close () 

# a + time required to read the file pointer to the front 
f = open ( 'C: \\ Users \\ LDH \ \ \\ 123.txt Desktop ',' + a ', encoding =' GBK ') 
f.seek (0) 
Print (f.readlines ()) 
# returns a list of each row as an element 
f.seek (0) # move the file pointer pointing to the beginning of the line 
Print (reached, f.read ()) 
f.close ()

f.writelines (list) 
# automatic cycle, each element in the list are written to the file 
L = [ '. 1 \ n-', '2 \ n-'] 
F = Open ( 'C: \\ \\ the Users of LDH \ \ \\ 123.txt Desktop ',' + A ', encoding =' GBK ') 
f.writelines (L) 
f.seek (0) 
Print (reached, f.read ()) 
f.close () 

file modify 
# efficient processing of documents 
# 1, a first method, first find the content to be modified and replaced, empty file, the contents of re-rewriting through replacement file 
f = open ( 'liudonghai.txt', 'a +', encoding = 'utf- . 8 ') 
f.seek (0) 
Result reached, f.read = () 
RESULT1 = result.replace (' wangyanquan ',' 123 ') 
f.seek (0) 
f.truncate () Clear file # 
f.write (result1) 
f.close () 
# 2, big files processed line 
Import OS 

F = Open ( 'liudonghai.txt', '+ A', encoding = 'UTF-. 8') 
F1 = Open ( 'liudonghai2.txt', 'w', encoding='utf-8')
f.seek(0)
Line F in for: 
    Line = line.upper () 
f1.write (Line) 
f.close () 
f1.close () 
The os.remove ( 'liudonghai.txt') 
os.rename ( 'liudonghai2.txt', 'liudonghai .txt ') 

# use with the open file does not need to use complete with automatically close off 
with open ( "liudonghai.txt") as f, open (' file path ') AS F2: 
    F = reached, f.read () 
F2. write ( 'xx')