python basis content ①
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What is python?
- A computer language, computer language into
- high-level language: python, java, Ruby, C #, C ++ ......
- base language: C language, assembly
- The computer can directly execute the basis of language, but the basic language is more complex, knocking a lot of trouble codes
- high-level language will be automatically converted into the base language, and then provided to the computer to perform.
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After installing python, print ( "hello world")
-python executable file extension can be arbitrary
- but in order to facilitate the implementation of pycharm, agreed to use commonly known as ".py" suffix
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The python implementation
- Input a "python execution file path is path" in cmd
- and a running python interpreter, enter the code and real-time execution
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The top of the code "#! / Usr / bin / env python" meaning
- Tell python path location Linux system, win system to ignore
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Top Code "# - * - coding: utf8 - * -" meaning
- comes encoder may not recognize Chinese, requires the interpreter to call uft8 encoder, 3.0 or later ignored
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How to use python simple interaction
- Usage [Learn input output system after waiting for user feedback, and then the next line of code]
input ( 'Please any input:')
print ( 'Well done!')
- Understand the assignment
n = input ( 'I really handsome')
print(n)
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A preliminary understanding of the significance of variables
- is the value of a variable changes over time
- variables can be made: constitute a "letter", "number", "underline"
- Variable writing rules:
Just how to write
But "can not start with a number," "Do not use python keyword" "Do not repeat the python built-in"
The system does not recognize the impact of running python python operational impact
- Note: Multi-word with "_" link, look professional
-
Understand the conditional statement (I prefer the judge called the statement) "if"
-format
if conditions:
how is it going
else：
how is it going
- Examples
if 1==1 :
print('ok')
else:
print('no')
- Learn to use under many conditions "elif"
- Learn about the statement can be nested
- a simple example:
n = input ( 'Enter a username')
IF n-== 'Male':
Print ( 'look to a photo')
elif n-== 'beauty':
Print ( 'micro-channel add chant')
elif n-== 'star':
Print ( 'sign your name to chant')
the else:
Print ( 'mud triumph')
#Print ( 'Nice to meet you')
- [no] skip is performed with the pass- [to write the English grammar symbol, or a variety of error]
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Basic data types
- String: quotation marks (English grammar under the symbol !!!)
n = 'I'm a guy'
n = '' I'm a guy ''
n = '' 'I'm a guy' ''
n = "I'm a guy."
n = "" I'm a guy. ""
n = "" "I'm a guy." ""
- Three quotes indicate when the comment branches displayed
- addition, subtraction [+ - * /]
addition:
a="jalskfgoas"
b="dasfase"
c=a+b
print(c)
jalskfgoasdasfase
multiplication:
= sda
b=a*2
print(b)
sdasda
- Digital has addition, subtraction, with no difference in a child's learning
- numbers in () are quoted in the print, is not calculated, the output string
- Supplementary: ** square, take the remainder%, // take quotient of the division (division calculations result rounded)
- Example: Write the code judgment odd and even
n=int(input('give me a number:'))
a1=n%2
if a1 == 0:
print ( 'even number')
Else:
print ( 'odd')Note that the first line to indicate the n is an integer, otherwise an error.