Python Learning Lesson Three

# Python development tool pycharm, software settings in File-setings settings font, style and mouse scrolling zoom out,
# What is a subsequence? A subsequence is a part of a character in a string, such as the Name= "Dongfeng" in a sequence. 
# One, digital magic
# 1. int turns a number in a string into an integer, converting the specified string to a specified number of  digits
#例:
# num1= "123456"
# V=int (NUM1)
# Print (v)
# c1= "L"
# V=int (c1,35)
# Print (v)
# 2. . Bit_length () calculates the minimum length after the specified number has been converted into 2 
# Example:
# v1=255
# v=v1.bit_length ()
# Print (v)
# Two, string magic 
# 1. . Capitalize () Capitalize the letter first letter 
# zm= "Wei"
# v=zm.capitalize ()
# Print (v)
# 2. . Casefold () turn all letters into lowercase, including other languages. Lower () also turns all letters into lowercase, but only the letters in English are lowercase. 
# char1= "WEI"
# v=char1.casefold ()
# Print (v)
# char2= "Lwei"
# v=char2.lower ()
# Print (v)
# 3. . Center () centers the characters and fills them with the specified characters. 
# char1= "China"
# V=char1.center ("*")
# Print (v)
# 4. . EndsWith () finds whether to end with the specified character, or False if it is returned; StartsWith () finds whether to start with the specified character, or False if it is true 
# c1= "Woshiwodewo"
# V=c1.endswith ("W")
# Print (v)
# c1= "Woshiwodewo"
# v=c1.startswith ("Wo")
# # Print (v)
# 5. . Find () looks for a specified character from within the specified range and cannot find the location found by-1. Do not specify a range to start with 0 bits. Index () Ndex and find, but Index can not find the error, we use. Find () as the main.
# c1= "ASDAFDGHDFGSFD"
# V=c1.find ("D", 3,8) #
# Print (v)#补充: When the specified position is started, the specified character position is counted starting at 0. 
# 6. The . Format () format character, replacing the variable in the {} placeholder with the character we specified;. Format_map ({}) replaces the variable in the {} placeholder with the character we specified, behind the map is a dictionary, note that two placeholders are "" and contain curly braces .
# example 1:
# str1= "My Name {name}, this year {age} years old"
# Print (str1)
# V=str1.format (name= "Ali", Age=18)
# Print (v)
# # example 2:
# str1= "My Name {name}, this year {age} years old"
# Print (str1)
# V=str1.format_map ({"Name": "Lilei", "Age":)
# Print (v)
# 7. The . Isalnum () determines if there are any special characters besides letters and numbers, and if there is a return false, no special characters are returned  to the True
# v1= "d1a23sd1a3d+0-09"
# v=v1.isalnum ()
# Print (v)

Python Learning Lesson Three