WRITING & READING TXT FILES WITH PYTHON 3 TXT FILES HAVE TO BE IN THE SAME FOLDER AS THE PROGRAM
WRITING TO FILE
HOW TO WRITE TO A TEXT FILE 1. CREATE A SUITABLE VARIABLE TO STORE THE NAME OF THE TEXT FILE. 2. USE THE CODE WRITE TO ADD TEXT TO THE FILE This means ‘write’ 3. CLOSE THE TEXT FILE This means ‘new line’
HOW TO WRITE TO A TEXT FILE NAME = OPEN("FILENAME", "W") NAME = OPEN("FILENAME", "A") • TRY THE ‘A’ • WHAT DOES IT DO? Change this w to a, what happens
DONALD SAYS……. CREATE CODE TO WRITE A LIST OF GAS PRICES IN THE USA TO A FILE: 8. 20 8. 08 8. 38 3. 81 3. 84 3. 92 3/21/11 3/28/11 4/4/11 CALL THE FILE ‘GAS PRICES. TXT’
READING FROM A FILE
READING FILES NAME = OPEN("FILENAME") NAME. READ() - FILE'S ENTIRE CONTENTS AS A STRING NAME. READLINE() - READ NEXT LINE FROM FILE AS A STRING NAME. READLINES() - FILE'S CONTENTS AS A LIST OF LINES f = open("hours. txt“, “r”) print(f. read())
DONALD WANTS YOU TO……. CREATE CODE THAT: 1. ASKS THE USER TO ENTER IN A SENTENCE 2. SAVES THE SENTENCE TO A FILE 3. CREATE A NEW TEXT FILE WITH THE SENTENCE “MAKE MERICA GREAT AGAIN!” 4. SAVE IT AS A FILE CALLED USA. TXT 5. ADAPT THE PROGRAM TO READ THIS FILE 6. USE STRING SKILLS TO PRINT THE LAST WORD
print mystring[-1] # print last char print mystring[5: -1] # result 5678 print mystring[: -1] # everything but the last char print mystring[4: ] # from position 4 and onward print mystring[8: 100] # result 89