Today I'll summarize the number and string types in data types.

Preview:

# Write code,There are the following variables,Please implement each function as required (6 points, 0 for each sub-item).5 Points)
name = " aleX"
# 1)    remove name Spaces on either side of the corresponding value of a variable,And output the processing results.
# 2)    judge name Does the value of a variable correspond to "al" Start,And output the results

# 3)    judge name Does the value of a variable correspond to "X" Ending,And output the results

# 4)    take name In the corresponding value of a variable“ l" Replace with“ p",And output the results
# 5)    take name The corresponding value of the variable is based on“ l" Division,And output the results.
# 6)    take name Variables correspond to capitalized values,And output the results

# 7)    take name Variables correspond to lower case values,And output the results

# 8)    Output please name The second character of the value corresponding to the variable?
# 9)    Output please name The first three characters of a variable's corresponding value?
# 10)    Output please name The last two characters of the corresponding value of a variable?

# 11)    Output please name Among the values corresponding to variables“ e" Location of index?

# 12)    Acquisition of subsequences,Remove the last character. as: oldboy Acquisition oldbo. 

 

I. Digital (int, float)

In Python 3, the number types are only shaping, floating-point and complex. The complex number is hardly used in ordinary programming, so we only need to master shaping and floating-point type. (long shaping cancels the unified shaping in Python 3, so the shaping length is unlimited in Python 3)

Integral int: grade, age, grade, ID number, qq number, mobile phone number, etc.

ps:

level=10

Floating-point float: height, weight, salary, temperature, price

ps:

height=1.81

salary=3.3

1 n = 12
2 f = 1.5
3 print(type(n)) # int That's plastic surgery.
4 print(type(f)) #float That's floating point type.
5 
6 #Scientific Counting Method python Application: (10 uses) e Substitution)
7 print(1.3e-3)    #1.3e-3 --> 0.0013
8 print(1.3e3)    #1.3e3 --> 1300.0

Characteristics of digital types:

1. Only one value can be stored

2. Once defined, unchangeable

3. Direct access

2. String type

Included in quotation marks (single, double, three), it consists of a string of characters

Uses (descriptive data): name, gender, address, educational background, password, etc.

ps:

 1 s1 = 'lln'
 2 s2 = "lln"
 3 s3 = '''lln'''
 4 s4 = """lln"""
 5 
 6 print(type(s1))
 7 print(type(s2))
 8 print(type(s3))
 9 print(type(s4))
10 #All are str String type

Value:

First of all, it should be clear that the whole string is a value, but the special point is that there is no character type in python. The string is composed of a string of characters. If you want to extract the characters in the string, you can also get them by subscript.

ps:

name = "lln"

name: Gets the value (lln) that is the whole string.

name[1]: Gets the character (l) that is the second position.

String splicing:
msg1='hello'
msg2=' world'
The use of + in a string:
msg1 + msg2
'hello world'
res=msg1 + msg2
print(res)
hello world
The use of * in strings:
msg1*3
'hellohellohello'

Note: Strings can no longer use other symbols.

Common String Method Full Solution:

#Remove spaces or characters on both sides
name = "   llN***"
print(name)
print(name.strip("*"))

#Judging what ends and begins
name = "lln"
print(name.endswith("l"))  #false
print(name.startswith("l"))  #true

#replace
name = "lln"
print(name.replace("n","N"))  #llN
print(name.replace("l","L"))  #LLn
print(name.replace("l","L",1))  #Lln 1 Specified number of substitutions

#format string
str = "name:{},age:{},sex{}"
print(str)  #name:{},age:{},sex{}
print(str.format("lln",22,"man"))  #name:lln,age:22,sex:man
str = "name:{0},age:{1},sex{0}"
print(str.format("lln",22))  #name:lln,age:22,sex:lln
str = "name:{x},age:{y},sex{z}"
print(str.format(y=22,x="lln",z="man"))  #name:lln,age:22,sex:man

#Indexes
name = "lln love"
print(name.find("o"))  #Return location
print(name.find("a"))  #Search cannot return-1
#Indexing
print(name.index("o")) #Indexes o position
print(name[4])
print(name[name.index("o")])
#Character statistics
print(name.count("l"))  #Letter l Number of occurrences
print(name.count("l",0,4))  #Statistics 0-3 Median l Number of occurrences

#segmentation
name = "hello world"
print(name.split())  #['hello', 'world']Separated by space by default
name = "he:llo wor:ld"
print(name.split(":"))  #['he', 'llo wor', 'ld']Separators can be specified
print(name.split(":", 1))  #There are two parts.

# join Connect string arrays.
name = " "
print(name.join(["lln", "say", "hello", "world"]))  # Iterable objects must all be strings

#center,ljust,rjust,rfill Its format
name = "lln"
print(name.center(30,"-"))
print(name.ljust(30,"*"))
print(name.rjust(30,"*"))
print(name.zfill(50))  #Fill in with 0

#expandtabs Replace tabs“\t' Number of characters of
name = "lln\thello"
print(name)
print(name.expandtabs(1))

#small-caps(A lowercase letter)
name = "lln"
print(name.upper())
name = "LLN"
print(name.lower())
#To determine whether capitalization (lowercase) is necessary, all capitals or lowercases must be capitalized.
name = "lln"
print(name.isupper())
print(name.islower())

# captalize,swepcase,title
name = "lln"
print(name.capitalize())  #title case
name = "LlN"
print(name.swapcase())  # Case reversal
msg = "lln say hi"
print(msg.title())  # Capital letters for each word
# Judging capitalization of initial letters
name = "Lln"
print(name.istitle())

#Value and slice
name = "hello world"
print(name[0])  #h
print(name[6])  #w
#print(name[20])  Report errors
print(name[-1])  #d
print(name[-3])  #r
print(name[1:3])  #el Section
print(name[1:5])  #ello Section
print(name[1:5:3])  #eo Section 3 is step size

#Determine whether a string can be converted to a number
# age=input('age: ')
# if age.isdigit():  #If user input 12 returns true If abc Then return false
#     new_age=int(age)
#     print(new_age,type(new_age))

#Is the judgement blank?(Must be all blanks)
name = ""
print(name.isspace())
name = "   "
print(name.isspace())

print("===>")
name = "egon123"
print(name.isalnum())  # Strings consist of letters and numbers
print(name.isalpha())  # Strings consist of only letters

 

Preview Answer:

# Write code,There are the following variables,Please implement each function as required
name = " aleX"
# 1)    remove name Spaces on either side of the corresponding value of a variable,And output the processing results.
print(name.strip())
# 2)    judge name Does the value of a variable correspond to "al" Start,And output the results

print(name.startswith("al"))
# 3)    judge name Does the value of a variable correspond to "X" Ending,And output the results

print(name.endswith("X"))
# 4)    take name In the corresponding value of a variable“ l" Replace with“ p",And output the results
print(name.replace("l","p"))
# 5)    take name The corresponding value of the variable is based on“ l" Division,And output the results.
print(name.split("l"))
# 6)    take name Variables correspond to capitalized values,And output the results

print(name.upper())
# 7)    take name Variables correspond to lower case values,And output the results

print(name.lower())
# 8)    Output please name The second character of the value corresponding to the variable?
print(name[1])
# 9)    Output please name The first three characters of a variable's corresponding value?
print(name[0:3])
# 10)    Output please name The last two characters of the corresponding value of a variable?

print(name[-2:])
# 11)    Output please name Among the values corresponding to variables“ e" Location of index?

print(name.index("e"))
# 12)    Acquisition of subsequences,Remove the last character. as: oldboy Acquisition oldbo. 
print(name[0:-1])