Detailed Explanation of Python String

Directory 1. Partial escape characters 2. slice slice read string 3. Call split () method to split string ASCII letter 4. Method related to letter case 5. Search lookup string summary

1. Partial escape characters

 Escape character 
# \\  Backslash 
str1 = "qqq\\qq"
print(str1)
#  Output  qqq/qq
# \b  Backspace key ( Backspace ) 
str2 = "qqq\b"
print(str2)
#  Output  qq
# \'  Single quotation mark  \" Double quotation marks 
str3 = "qq\'qqqqq\""
print(str3)
#  Output  qq'qqqqq"
# \n  Line break 
str4 = "qqqq\nqq"
print(str4)
#  Output  qqqq
#     qq
# \t  Tabs ( Tab ) 
str5 = "a\taa"
print(str5)
#  Output  a   aa

2. slice slice read string

s = "hello world sssss sssss sssss"
# s[n]  Specifies that the subscript reads an element in the sequence 
print(s[1])
# e
# s[n: m]  From subscript value n Read to m-1 , several elements 
print(s[0: 4])
# hell
# s[n:]  From subscript value n Read to the end 1 Elements 
print(s[3:])
# lo world
# s[:m]  From subscript value 0 Read to m-1 Elements 
print(s[:5])
# hello
# s[:]  Indicates that it will be copied 1 Elements of a partial sequence 
print(s[:])
# hello world
# s[::-1]  Invert the whole sequence element 
print(s[::-1])
# dlrow olleh

3. Call the split () method to split the string ASCII letter

#  String .split( Delimiter, number of separations) 
#  Output 26 Lowercase letters and invert the output 
letters = ""
for x in range(97, 123):
    letters += str(chr(x))
print(letters)
print(" ")
print(letters[::-1])
# ord() Returns the corresponding character ASCII Code 
# chr() Return ASCII Characters corresponding to code 
#  Output 26 Uppercase letters and invert the output  A 65 Z 91
letters2 = ""
for n in range(65, 91):
    letters2 += chr(n) + " "
print(letters2)
print(letters2[::-1].split(" ",5))  #  String .split( Delimiter, number of separations) 

4. Methods related to letter case

str = "My name in Zyj hello world"
# capitalize()  Only the first 1 The first letter of the word is capitalized and the rest is lowercase 
print(str.capitalize())
# My name in zyj hello world
# lower()  Convert letters to lowercase 
print(str.lower())
# my name in zyj hello world
# upper()  Convert letters to uppercase 
print(str.upper())
# MY NAME IN ZYJ HELLO WORLD
# title()  The first letter of each word is capitalized and the rest is lowercase 
print(str.title())
# My Name In Zyj Hello World
# islower() isupper() istitle()  Determine whether the string conforms to the format 
print(str.isupper())
# False

5. Search for lookup strings

str1 = "Myaa namess inddaa Zyjcc helloxx worldbb"
# 1.count.py  Search for the number of specific strings that exist 
print(str1.count("aa"))
# 2. Lookup string   str.find( Character or string   Beginning subscript , End subscript )  Return to the 1 The subscript number the next time the string is found 
# find The () method returns when it does not find a substring  -1
str2 = "My name in Zyj hello world My name in Zyj hello world"
print(str2.find("in", ))  #  Looking for substrings in , numbered from the subscript 0 Begin 
print(str2.find("in", 9))  #  Looking for substrings in , numbered from the subscript 9 Begin 
# 3. str.index( Character or string   Beginning subscript , End subscript )  Returns the subscript value of the specified string 
print(str2.index("name"))
# index  And  find  Difference, index () If you can't find it, you will report an error. find () returns  -1  Value 
# 4.startswith( Character or string   Beginning subscript , End subscript )  Determine whether the beginning character of a string contains subcharacters 
str3 = "My name in Zyj hello world My name in Zyj hello world"
print(str3.startswith("name", 3))  # True
# 5.str.endswith( Character or string   Beginning subscript , End subscript )  Determine whether the character at the end of the string contains subcharacters 
print(str3.endswith("world"))  # True

Summarize

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