Python Basics (ii)

• Cycle

  For

• Name_k = [' teng ', ' Cardinals ', ' Rommel ']

• For i in name_k:if i = = "Cardinals": print "Super Bowl is%s"% i

  
  

  Note And if are used together

While try not to use

For is the efficiency of Python optimization is high

Break: Please debug the following code to understand break

For i in name_k:if i = = "Cardinals": print "Super Bowl is%s"% i break if i = = "Rommel": print "This is Romme L

Continue: Please debug the following code to understand continue

For i in name_k:if i = = "Cardinals": print "Super Bowl is%s"% i continue if i = = "Rommel": print "This is RO Mmel "

• Dictionary

• Key-value pairs
• 
  
• 
  

man={"name": ' Cardinals ', ' age ': "Gender": "Male"}

man[' name ']

Dictionaries and for

For k in Man:print Man[k]

For k,v in Man.items (): Print k,v

The characteristics of a dictionary

Disordered

Unique methods

1. Man.items ()

2. Man.keys ()

3. Man.values ()
   

• Operation of the text

  Text: Persisting

1. Find File

2. Open File

3. Read and write operations

4. File Close
   

File (path, ' mode ')

Mode

R: Read-only

W: Write only (invalid original file)

A: Append

r+: After reading it again

w+: Delete Content again

A = file (' Test ', ' R ') print A.readlines () a.close ()

Method

READ: Reading a file into memory

ReadLines: Reads the file into memory and takes a newline character as a delimiter, and then gets a list

Write: Finish once

WriteLine: Line Write

A = file (' Test ', ' r+ ') file_list = A.readlines () for i in file_list:line = I.strip () values = Line.split (';') Last_value=int (Values[-1]) last_value+=1 values[-1]= last_value print valuesa.close ()

Code instance

#!/usr/bin/env python#-*-coding:utf-8-*-__author__ = ' teng ' F = file (' Test ', ' r+ ') fileList = F.readlines () mylist =[]for    I in filelist:line = I.strip () valueList = Line.split (';') Lastvalue=int (Valuelist[-1]) Lastvalue + = 1 Valuelist[-1] = str (lastvalue) #print values valuestr = '; '. Join (valueList) mylist.append (valuestr) mystr = ' \ n '. Join (mylist) str= ' \ n ' +mystrf.write (str) f.close ()

The test file was originally

Hello Fdf;3rommel;dfds;5

After running the script:

Hello Fdf;3rommel;dfds;5hello; Fdf;4rommel;dfds;6

For explanations of operation, please search by yourself

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Python Basics (ii)