Python basic syntax

1. Input and output cycle judgment

num=10Bingo=False whilebingo==False: #False的写法要注意 answer=input ()ifanswer<Num:Print 'too small'     ifAnswer>Num:Print 'too Big'     ifanswer==Num:Print 'BINGO'Bingo=true

 for  in range (1,21):                  #从1循环到20    print i                             #  Note that there must be a first line indent

Formatted output:

>>> num=18>>>Print 'My Age is%d'%Nummy Age is18>>>Print 'Today is%s.'%'Friday'Today isFriday.>>>Print "%s ' score is%f"%('Lily', 90.2) Lily'score is 90.200000>>>Print "%s ' score is%.2f"%('Lily', 90.2) Lily'score is 90.20

 for  in range (0,5):    for in range (0,i+1):        print'  * ',                 # to output on the same line, followed by a comma    print                       # output Empty, Will change line

2. The main record is different from the C language and where special attention is needed:

// divisible

* * exponentiation

Integers have no length limit, floating-point numbers are limited by length (16 digits after the decimal point)

Plural:

>>> 1j*1j ( -1+0J)

3. Import the module:

Import

①import Math #导入math中所有函数 Use MATH.SQRT () in the form of

②from Math Import * #导入math中的所有函数, can be used directly sqrt ()

③from Math import sqrt, tan #只导入sqrt和tan两个函数 recommended

>>> Import math>>> math.sqrt (5) 2.23606797749979>>> math.sqrt (2) *math.tan (22) 0.012518132023611912>>> from math import *>>> log (25+5) 3.4011973816621555>>> sqrt (4) *sqrt 20.0>>> from math import sqrt, tan>>> tan (*sqrt) (4) 4.474321888449484

4. String : "," "," "" "" "

Len (): The length of the string itself is returned by the shape of the string, not like C.

+: string concatenation

*: Multiple splicing

" " "What ' s your name?" I asked. " I ' m Han meimei. " " " ' \ n "What\ 's your name?" I asked.\n "I\ ' m Han Meimei." \ n"" Thesameline"This is thesame line '

str="What' s your name?" I asked. " I ' m Han meimei. " " " Print str

The results obtained:

"What ' s your name?" I asked.
"I ' m Han Meimei."

5. Help:

dir (): The module name after the module is imported in parentheses, listing all functions of the module

dir (__builtins__): See a list of Python built-in functions

Help (): The function name in parentheses to see the function's document string

Print (): printing function Document string

such as: Print (math.tanh.__doc__)

Print (bin.__doc__)

6. Type conversion:

float (): Converts integers and strings to floating-point numbers

str (): converting integers and floating-point numbers to strings

int (): Converting floating-point numbers and strings to integers discarding fractional parts of a string must look like an integer "123.5" is not possible int (' 325 ') is OK

round (): floating point to Integer quad six in 50% double unsupported string

>>> str (3.1415) ' 3.1415 ' >>> float (' 3 ') 3.0>>> int ("123") 123>>> int ("123.5") Traceback (most recent):  File "<pyshell#30>", line 1, in <module>    

7. Multiple assignments:

>>> x,y,z=1, "R",1.414>>> x1>>> y ' r ' >>> z1.414

Value of the interchange variable

>>> y,x=x,y>>> x ' r ' >>> y1

8.random

 from Import randinti=randint (5,10)print i

Python basic syntax