练习一：自己定义一个reverse(s)函数，功能返回字符串s的倒序字符串。
In [1]:
def reverse(s):
rev_s = [0]*len(s)
for i in range(len(s)):
rev_s[len(s)-i-1] = s[i]
s = rev_s
print (s)
s = [1,2,3,4,5,6,7,8]
reverse(s)
练习二：写函数，根据给定符号和行数，打印相应直角三角形，等腰三角形及其他形式的三角形。
In [3]:
def play_triangel(symbol,line_num):
print ('直角三角形：') #加上列号似乎有多种，其余同理
for i in range(line_num):
print (' '*(line_num-i-1)+symbol*(i+1))
print ('等腰三角形：')
for i in range(line_num):
print (' '*(line_num-i-1)+symbol*(i)+'*'+symbol*(i)+' '*(line_num-i-1))
print ('其他三角形：') #不是很懂，其余？
for i in range(line_num):
if i < line_num//2:
print (' '*(line_num-i-1)+symbol*(i+1))
else:
if line_num%2 == 0:
j = line_num-i-2
else:
j = line_num-i-1
print (' '*(line_num-j-1)+symbol*(j+1))
symbol = '*'
line_num = int(input("请输入行号，回车结束："))
play_triangel(symbol,line_num)
练习三：将任务4中的英语名词单数变复数的函数，尽可能的考虑多种情况，重新进行实现。
In [4]:
#写成英语名词了，就不写动词了
def sin_to_plu(Eng_word):
if Eng_word.endswith('s') or Eng_word.endswith('x') or Eng_word.endswith('sh') or Eng_word.endswith('ch'):
print (Eng_word+'es')
elif Eng_word.endswith('y'):
print (Eng_word[0:len(Eng_word)-1]+'ies')
elif Eng_word.endswith('f') or Eng_word.endswith('fe'):
if Eng_word == 'safe' or Eng_word == 'roof': #这特殊情况能列举不完
print (Eng_word+'s')
elif(Eng_word.endswith('f')):
print (Eng_word[0:len(Eng_word)-1]+'ves')
else :
print (Eng_word[0:len(Eng_word)-2]+'ves')
elif Eng_word.endswith('o'):
if Eng_word == 'tomato' or Eng_word == 'tomato' or Eng_word == 'hero' or Eng_word == 'negro': #这特殊情况能列举不完
print (Eng_word+'es')
else :
print (Eng_word+'s')
#elif #不规则的单词 就不写了
else :
print (Eng_word+'s')
while True :
Eng_word = input('请输入一个要转换的英语单词，回车结束,输入‘q’结束 ')
if Eng_word == 'q':
break
sin_to_plu(Eng_word)
练习四：写函数，根据给定符号，上底、下底、高，打印各种梯形。
In [5]:
def play_trapezium(symbol,upper_line,lower_line,height):
print ('trapezium：')
for i in range(height):
print (' '*(lower_line-upper_line-i)+symbol*(i+upper_line))
symbol = '*'
upper_line = int(input("请输入梯形上底，回车结束："))
lower_line = int(input("请输入梯形下底，回车结束："))
height = int(input("请输入梯形的高，回车结束："))
play_trapezium(symbol,upper_line,lower_line,height)
练习五：写函数，根据给定符号，打印各种菱形。
In [7]:
def play_rhombus(symbol,line_num):
print ('rhombus：')
for i in range(line_num):
if i < line_num//2:
print (' '*(line_num-i-1)+symbol*(i)+'*'+symbol*(i)+' '*(line_num-i-1))
else:
if line_num%2 == 0:
j = line_num-i-2
if (i != line_num-1):
print (' '*(i+1)+symbol*(j)+'*'+symbol*(j)+' '*(i))
else:
j = line_num-i-1
print (' '*(i)+symbol*(j)+'*'+symbol*(j)+' '*(i))
symbol = '*'
line_num = int(input("请输入行数，回车结束："))
play_rhombus(symbol,line_num)
练习六：加密解密文件
In [1]:
import random
def compute_rand_key():
rand_num = [0]*9
for i in range(9):
rand_num[i] = random.randint(0,9)
return rand_num
def compute_rand_letter():
rand_letter = random.randint(65,122)
while rand_letter >= 91 and rand_letter <= 96:
rand_letter = random.randint(65,122)
return rand_letter
def encode(rand_key,word_len):
file_in = open('F:\\python\\419test.txt','r')
file_out = open('F:\\python\\419test_new_out.txt','w')
for line in file_in:
symbol = '.,?'
for s in symbol:
line = line.replace(s,' ')
line = line.split()
for word in line:
word_len.append(len(word))
key = rand_key.copy()
key.append(len(word))
word_new = []
for i in range(len(word)):
ascii_i = ord(word[i])
#ascii_i >> int(key[i])
ascii_i += int(key[i])
ascii_i = chr(ascii_i)
word_new.append(ascii_i)
for j in range(len(word),10): # len(word)要如何保存下来
rand_le = compute_rand_letter()
word_new.append(chr(rand_le))
word_new = "".join(word_new)
#print (word_new)
file_out.write(word_new+' ')
file_in.close()
file_out.close()
def decode(rand_key,word_len):
file_in = open('F:\\python\\419test_new_out.txt','r')
file_out = open('F:\\python\\419test_old_out.txt','w')
for line in file_in:
print (line+'\n解密后的文件：')
line = line.split()
j = 0
for word_new in line:
rand_key.append(len(word_new)) ###如何得到原来的len(word)即字符的长度
key = rand_key.copy()
word_old = []
for i in range(int(word_len[j])):
ascii_i = ord(word_new[i])
#ascii_i << int(key[i])
ascii_i -= int(key[i])
ascii_i = chr(ascii_i)
word_old.append(ascii_i)
word_old = "".join(word_old)
j += 1
print (word_old)
file_out.write(word_old+' ')
file_in.close()
file_out.close()
def main():
file_in = open('F:\\python\\419test.txt','r')
print ('加密前的文件：')
for line in file_in:
print (line)
word_len = []
rand_key = compute_rand_key()
encode(rand_key,word_len)
print ('加密后的文件：')
decode(rand_key,word_len)
print (''' -----------------分割线-----------------
问题：
1.原来单词的长度再现困难，是否是我题意理解错了
2.移位问题
-----------------分割线-----------------''')
if __name__ == '__main__':
main()
练习七：与本小节任务基本相同，但要求打印回文字符倒三角形。
In [2]:
def plalindrome(line):
for i in range(len(line)*2,0,-1):
if i == 1:
print( line[0] + ' '*(len(line)*2-1))
elif i%2 == 1:
print(line[:i//2] + line[i//2] + line[i//2-1::-1] +' '*(len(line)*2-i) )
else:
print(line[:i//2] + line[i//2-1::-1] + ' '*(len(line)*2-i) )
def main():
text = '赏花归去马如飞'
plalindrome(text)
if __name__ == '__main__':
main()