4.12 input() input function and comments

Python Knowledge framework diagram ：

4.12.1 Built in functions

Definition ： The built-in function is Python Self contained functions , install Python You can use it directly .
grammar ： Function name （ Parameters ） for example ：print(‘520’)

4.12.2 input( ) Input function

print( ) and input( ) Are built-in functions .
print( ) Output function .
input( ) Input function .

【 Experience code 】

name = input(' Please enter your name ：')
print(name)

【 Terminal output 】
Andy

Run the above code , A blank box will appear at the top of the page ;
I type my name in the box Andy , Then press enter ;
Name I entered Andy Will be input( ) Function receive ;
Then assign the received content to the variable name;
use print( name ) Call variables name, Name I entered Andy It is displayed at the bottom of the code box .
This completes the input and output of the computer .
The simple understanding is ： function input( ) After the function , The computer asks you to enter your name , After you enter your name, the computer receives your name and stores it , And then use print( ) The function outputs the name you just entered , The communication between human and computer is simply completed .

input The contents in function brackets are suggestive , Will not be output by the program .
In the code above, only Andy , Please enter your name ： This string of characters is not output .

4.12.3 input The input content data type of the function is string

#  use input  Function to enter a Chinese sentence , And assign to variable 
gift = input(' What do you want for Valentine's day ？')

#  Check the variable 
print(gift)

#  View data types of variables 
print(type(gift))

【 Terminal output 】
The roses
<class ‘str’>

The first line outputs The roses It's what I entered ;
The second line class ‘str’ Indicates what I entered The roses The data type is string .

#  use input  Function to enter an integer , And assign to variable 
int_1= input(' What's your favorite number ？ Please enter an integer :')

#  Check the variable 
print(int_1)

#  View data types of variables 
print(type(int_1))

【 Terminal output 】
7
<class ‘str’>

The first line outputs 7 It's what I entered ;
The second line class ‘str’ Indicates what I entered 7 The data type is string .

#  use input  Function to enter a floating point number , And assign to variable 
float_1= input(' What's the oil price today ？ Please enter a floating point number :')

#  Check the variable 
print(float_1)

#  View data types of variables 
print(type(float_1))

【 Terminal output 】
8.4
<class ‘str’>

The first line outputs 8.4 It's what I entered ;
The second line class ‘str’ Indicates what I entered 8.4 The data type is string .

Through the above 3 Segment code , We found that , No matter what type of data we enter at the terminal ,input After the function receives , The resulting data types are strings .

Practice after class 1

The completion code , use input( ) The function inputs two integers , Then output the sum of two integers , Be careful ：input The data type of the input content is string .

'''  use input  The function inputs two integers , And assign to variable   First integer input ：10  Second integer input ：20 '''

#  Calculate the sum of two integers 


#  Output this sentence as it is ：10+20 be equal to 30

Practice after class 2

#  My salary is... Per month 9000 element , Create a new variable to store salary 


# input Function to enter your daily consumption , Create a new variable to store the input content 


#  Calculation 30 How much money do you have left in days ？


#  Original output ：30 Days later, I still have xxx element .

4.12.4 Basic knowledge of ： notes

Comments explain the code , Will not be run by the program .
There are three ways to annotate ：
Method 1 ：#
Method 2 ：'''
Method 3 ："""
The above punctuation marks are input under the English input method , Because I write notes in the text input box , Not in code box , So the display is different .

Method 1 ：#

#  This is the first line of comment 
#  This is the second line of comment 

Method 2 ：'''

'''  This is the first line of comment   This is the second line of comment  '''

Method 3 ："""

"""  This is the first line of comment   This is the second line of comment  """