One of the basic data types of python

Basic data types of python

int 

#   int
# Convert string to number
# a='123a' cannot be changed
a = "123"
b = int(a)
print(b)
print(type(b)) # check the type of an element

# The ascii value is converted here, if it is more than one character, it cannot be converted
a = 'b'
b = int(b)
print(b)   
 
# Base conversion, convert to binary,
num = "0011"
v = int(num, base=2)
print(v)

# The binary of the current number, represented by at least a few bits
age = 10
r = age.bit_length()
print(r)

range 

# Create consecutive numbers from 7 to 2, subtracting 2, 7, 5, 3 each time
v = range(7, 1, -2) # -2 is the step size
for i in v:
    print(i)

Common String Methods

test="hello world"

# replace, replace ("aa", 'b'), replace aa with b, you can add a few replacements at the end
# Commonly used join, split, find, strip, upper, lower, replace must be able to

join adds other in each element

test = 'You are the wind and I am the sand'
print(test)
t = '*'
v = t.join(test)
print(v) # There is one more space in each

  result:

You are the wind and I am the sand --> you *is* the wind*er *I *is* the sand

split split string

# split string
# split(self, sep=None, maxsplit=-1)
test = "absadfsfff"
# Split all, if you add parameters later, it is split several times
v2 = test.split('s') # split by s
print(v2, type(v2))

result:

    ['ab', 'adf', 'fff'] <class 'list'>

find finds a substring

# Find the position where the substring appears for the first time, and there is another rfind that searches from the back to the front, and returns -1 if it is not found
# find(self, sub, start=None, end=None)
test = "hello"
v = test.find('lo')
print(v)

Result: 3

replace

# The last parameter is the number of replacements
# replace(self, old, new, count=None)
test = "hello"
v = test.replace("ll", 'tt')
print(v)
# result
# hetto

strip removes whitespace, or other characters

lstrip(self, chars=None)
# Remove left and right whitespace, including newlines
# or remove the specified character
test = '\nAlex '
l_v = test.lstrip()
r_v = test.rstrip()
v = test.strip()
print(l_v, r_v, v)

Alex  
Alex Alex

upper and lower to uppercase or lowercase

test  = "hello"
v = test.upper()
print(v) # all uppercase
v = test.lower()
print(v) # all lowercase

slice

# Get a certain character in the string, some are sliced
test = "abcde"
v = test [0]
v2 = test[1:2] # exclude 2
v3 = test[:-1] # first after
# string length
v4 = len (test)

# Strings cannot be modified once created,
# Once modified or spliced, a new string will be generated (open up a new space), which is true in many languages

Other ways to learn

# # case conversion
# test = "hello WORLD"
# v = test.swapcase()
# print(v).... There are many more, see the source code

#Determine    whether the string contains only letters or numbers ,
 #Whether    it is letters and Chinese characters ,   whether it is a number    islower is lowercase ,
 # isalnum(), isalpha, isdecimal isdigit isidentifier islower ,
 # isnumeric isprintable isspace istitle isupper