calculator.md

Use python as a normal calculator in the interactive mode

try to input expression

2 + 2 50 - 56 (50 - 56) / 4 8 / 5 3.e10 / 10

spacial operator: the difference between / and //

10 / 3 # gives you answer as accurate as possible 10 // 3 # ignores the decimal part 10 % 3 # shows the remainder of the division 10 ** 2 # means the power of 2

variable

price = 10 item = 3 cost = price * item

position_start = 0 position_end = 10 time = 4 velocity = (position_end - position_start) / time

recent answer

1 + 1 # shows 2 _ + 3 # shows 2 + 3 = 5

String, content embraced by '

s = 'Hello!' a = s + s b = s * 3

to control the string, using \t \n

s = 'Hello\tWorld\n' # t stands for tab and n stands for new line

string can be treated as an array/list (read only)

s = 'Hello World' s[0] # array/list operator [] s[3:4] # range from 3 to 4-1 s[3:7] # range from 3 to 7-1

List

l = [1, 4, 8, 16, 25] # isotropic l[0] # array/list operator [] l[-1] # circling back from the end, in this case is 25 l[-2:] l[-2:3] l[2] = 3 * 3 l[2:4] = [] # remove element from 2 to 4-1 l[:] = [] # empty all l.append(216) # append new number

char list

letters = ['a', 'b', 'c', 'd', 'e', 'f', 'g']

length of list

len(letters)

list in list

a = ['a', 'b', 'c'] b = [1, 2, 3] c = [a, b]

Workout

number guessing

star pattern

     *
    **
   ***
  ****
 *****
******

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