Common methods for python strings and simple read and write operations on files

result=() # Remove spaces and newlines on both sides of a string by default
print(result)

s1=('c') # If a value is passed, the passed character is removed by default on both sides
print(s1)

print(()) # Remove left space
print(()) # Remove right space

print(('c')) # Find subscripts. An error is reported when it does not exist; when the same character exists, the first position is returned
print(('c')) #look for subscripts。Returns when it does not exist-1

print(()) # Initial capitalization
print(()) # Make it all uppercase. For example, the checksum of a CAPTCHA is not case-sensitive
print(()) #All lowercase.

print(('4','e')) # Replace the character c with e. When the replaced character does not exist, no error will be reported and no replacement will be made.
print((' ','')) # Remove all spaces and replace them with an empty character
print(('c','fe',1)) #The third parameter indicates how many characters need to be replaced，Replace all if not written

print(('.jpg')) # Determine if an image ends in xxx. For example, to upload an image you need to determine if it ends in .jpg
print(''.endswith('.jpg'))

print(('y')) # Determine if it starts with xxx.
print('efg'.startswith('e'))
#True: True; False: False Boolean, used to do the judgment with the

print('Welcome on board'.center(50,'*')) #Specify the total length50，Place the characters in the center，If it's not long enough，expense or outlay*make up a deficiency

print('1'.zfill(5)) #Auto-completion when the string is not long enough0

print(()) #Occupy
print(s.format_map()) # Pass a dictionary

# %s order needs to be one-to-one; format doesn't need to be concerned with order
username='abc'
today='2019-03-30'
s2='wellcome{}make landfall (of typhoon etc)，Today's date is{}.'
print((username,today))

s3='insert into user value({username},{password},{phone})'
#format
new_s3=(password='123',username='abc',phone='110')

#format_map
new_s3=s3.format_map({'password':123,
           'username':'ccc',
           'phone':110
           })
print(new_s3)

print('123.1'.isdigit()) #Determine if the number is an integer，is returnedtrue，Otherwise, returnfalse

# Determine whether there are one or more spaces, if it is a space then return True, otherwise return False
print('abc'.isspace()) 
print(' '.isspace())

print('123'.isalnum()) # Judgment returns True as long as there are no special characters, such as numbers or letters; False if there are special characters

print('abc'.isalpha()) Returns True if # is not a number or a special symbol.

users='abc,xiaozi,xiaobai,xiaohei,xiaoming,xiaolan'
users2='abc xiaozi xiaobai xiaohei  xiaoming xiaolan'
# Requirements: the account number and password to become --- 'szz-abc',123456, if it is a string there is no way to deal with it, you need to use the array
# The above strings are comma-separated, so you can split each character by a comma and then take the value

result=(',')
#1. Split by some string;
#2, put the split elements into a list. Return result: ['abc', 'xiaozi', 'xiaobai', 'xiaohei', 'xiaoming', 'xiaolan']

result=('.')
#3, if the specified string does not exist, then put the entire string into the list, return results: ['abc,xiaozi,xiaobai,xiaohei,xiaoming,xiaolan']

result=()
#If split is not specified, it will split by spaces, no matter how many spaces there are in between, return result: ['abc', 'xiaozi', 'xiaobai', 'xiaohei', 'xiaoming', 'xiaolan'].
print(result)

# Convert list to string
names=['abc', 'xiaozi', 'xiaobai', 'xiaohei', 'xiaoming', 'xiaolan']
print(','.join(names))
#1, turn the list into a string
#2、Use the specified string to replace thelistEvery element inside is connected

# Write strings to files
f=open('','w',encoding='utf-8')
(','.join(names))
()

#Read the file; will report an error if the file name does not exist
f=open('','r',encoding='utf-8')
res=()
print('Data read from inside the file:',res)
()