think python学习心得-（5）迭代与字符串的使用

for while return break等语句，用法同C语言很像。

      m=5.0
      def sqr(a):
       x=a
       y=(x+m/x)/2
      if abs(y-x)<0.00001:
      print y
      else:
       sqr(y)
      def sq(a):
       x=a
       y=(x+m/x)/2
       flag= abs(y-x)
      if flag < 0.00001:
      return y
      else:
       sqr(y)
      sq(m)
  
 

      import math
      def sqr(a):
       x=a
       y=(x+m/x)/2
      if abs(y-x)<0.00001:
      print y
      return y
      else:
       sqr(y)
      def sq(a):
       x=a
       y=(x+m/x)/2
       flag= abs(y-x)
      if flag < 0.00001:
      return y
      else:
       sqr(y)
      for i in range(9):
       j=float(i+1)
       m=j
      print j,math.sqrt(j),sq(j)
  
 

      import math
      def eval_loop():
      while True:
       line = raw_input('>')
      if line == 'done':
      break
      print eval(line)
       eval_loop()
      print 'Done!'
      eval_loop()
  
 

略。

8.字符串

练习8-1

      word='fruit'
      length=len(word)
      for i in range(length):
      print word[length-i-1]
  
 

      prefixs='JKLMNP'
      suffix = 'ack'
      for letter in prefixs:
      print letter+suffix
  
 

表示fruit中的全体字符

练习8-4

      def find(word,letter,i):
       index = i
      while index < len(word):
      if word[index]==letter:
      return index
       index = index+1
      return -1
      print find('Hellowordthisiszhangchangle!','s',2)
  
 

      def count(word,letter):
       count1 = 0
       length = len(word)
      for i in range (length):
      if word[i] == letter:
       count1=count1+1
      return count1
      print ('Please input a world and a letter to be counted')
      word1=raw_input('>')
      letter1=raw_input('>>')
      print count(word1,letter1)
  
 

      word='banana'
      index=word.count('a')
      print index
  
 

文章来源: zclhit.blog.csdn.net，作者：zclhit_，版权归原作者所有，如需转载，请联系作者。

原文链接：zclhit.blog.csdn.net/article/details/50988194