Python 入门练习 (list, array, for loop, while loop, numpy)
1- Create an empty list name “mylist”
1 mylist = [] 2 mylist # print mylist
2- Append the following floating point numbers to the list: 4.0, 2.2, 5.7, 3.5 (use mylist.append() 4 times )
1 mylist.append(4.0) 2 mylist.append(2.7) 3 mylist.append(5.7) 4 mylist.append(3.5) 5 mylist
3- Use a “for loop” to print the values contained in “mylist”, one at a time.
1 len_mylist = len(mylist) 2 3 for i in range(len_mylist): 4 print('mylist','[',i,']','=',mylist[i]) 5 6 """ # three quation marks mean comment for several lines 7 for i in mylist 8 print(i) 9 """ # three quotation marks mean comment for several lines
4- Use a “while loop” to print the values contained in “mylist”, one at a time.
1 i = 0 2 while i < len_mylist: 3 print('mylist','[',i,']','=',mylist[i]) 4 i += 1
5- Create a numpy array using the values contained in “mylist”. Name it “myarray”.
1 import numpy as np 2 myarray=np.array(mylist) 3 myarray
6- Use a “for loop” to find the maximum value in “mylist”
1 maxvalue = mylist[0] 2 for i in range(len_mylist): 3 if maxvalue < mylist[i]: 4 maxvalue = mylist[i] 5 print('The maximum value is ', maxvalue)
7- Use a “for loop” to find the minimum value in “mylist”.
1 minvalue = mylist[0] 2 for i in range(len_mylist): 3 if minvalue > mylist[i]: 4 minvalue = mylist[i] 5 print('The minimum value is ', minvalue)
1 # another example 2 def min(mylist): 3 minvalue = mylist[0] 4 for i in range(len(mylist)): 5 if mylist[i]<minvalue: 6 minvalue = mylist[i] 7 return (minvalue) 8 print('The minimum value is =', min(mylist))
8- Create the following list mylist2=[[1,2,3],[4,5,6],[7,8,9]]
1 mylist2 = [ [1,2,3], [4,5,6], [7,8,9] ] 2 mylist2 3 print(mylist2[0][0])
9- Using the modulus (%) command, print the index of all odd numbers in “mylist2”
1 for i in range(3): 2 for j in range(3): 3 odd_num = mylist2[i][j] 4 if (odd_num % 2) == 1: 5 print( '(', i, j ,')' )