Replace {} in C + + with strict indentation, which is simple and beautiful.
Variables do not need the traditional definition, system inference, similar to auto
Naming rules: combination of upper and lower case letters, numbers, underscores and Chinese characters
Note: case sensitive, the first character cannot be a number, not the same as reserved words
Comment ා comment one sentence, three quotation marks annotate multiple lines. Interestingly, three quotation marks are also strings
33 reserved words: (case sensitive)
and elif import raise global
as else in return nonlocal
assert except is try True
break finally lambda while False
class for not with None
continue from or yield
def if pass del
EX1:
Please write a program to convert the user’s input Fahrenheit to centigrade, or convert the input centigrade to Fahrenheit.
The conversion algorithm is as follows: (C represents centigrade, f represents Fahrenheit)
C = ( F – 32 ) / 1.8
F = C * 1.8 + 32
#TempConvert.py
Tempstr = input ("please enter temperature value:)
if TempStr[-1] in ['F','f']:
C = (eval(TempStr[0:-1])-32)/1.8
Print ("the temperature after conversion is {: 2F} C". Format (c))
elif TempStr[-1] in ['C','c']:
F = 1.8*eval(TempStr[0:-1])+32
The converted temperature is {: 2F} F ". Format (f))
else:
Print (wrong input format)1. Input() function: read string, parameter is prompt
2. eval() function: remove the quotation marks of strings and change them into corresponding types. This function is really amazing
3. Slice operation, open left and close right, Li [:: 2] can add step size finally, – 1 is inverse index
4. String format operation, very convenient in the string {}, followed by. Format(). :. 2F for character control, floating point number with two decimal places
EX2:
Prime test
from math import sqrt
n = int(input("Please input number:"))
for i in range(2,int(sqrt(n))):
if n %i ==0:
print(f"{n} is Not a prime number.")
break
else:
print(f"{n} is a prime number.")1. The range (a, B, step) function produces an iterative sequence with step size
2. F-strings format, treat parentheses as variables
pi =3.14159
print(f'pi ={pi:.2f}')“Pi = 3.14”
Base conversion
f'int:31,hex:{31:x},oct:{31:o}'
'int:31, hex:1f,oct:37'3. For else statement, else can be matched with for. If for normally executes 10000 loops, else will be executed.
EX3:
Print a simple triangle
n=int(input("Please input number:"))
for i in range(n):
print('*'*i) 
Compared with C + +, the string supports * operation, that is, repeated N times