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The syntax of the call to the print function with two parameters in Listing 3 is probably different from what you have seen in my previous modules. By default, the print function terminates each output line with a newline . Because the lines of text in the file already contain a newline, without the second parametershown in Listing 3 , the output shown in Figure 1 would be double-spaced. The inclusion of the second parameter in the call to the print function in Listing 3 prevents the print function from inserting an extra newline and inserts an empty string instead.

Append more text to the file

The code in Listing 4 begins by printing a blank line to cause the output shown in Figure 3 to be more readable.

Then the code in Listing 4

  • re-opens the file for appending,
  • writes two additional text lines into the file, and
  • closes the file.
Listing 4 . Append more text to the file.
print()#blank line to separate the output text #Append some text to the file.#Open the file object for appending. theFile = open("SampleTextFile.txt","a")#Append two more lines of text to the file. theFile.write("First appended line.\n")theFile.write("Second appended line.\n") #Close the filetheFile.close()

Read and print the file contents with a while loop

The readline method of a file object will read and return the next line from the file. An empty string is returned whenthe end of file is encountered. (There are some subtle ramifications that you can learn about at File Objects .)

The code in Listing 5 uses the readline method in a while loop to read and print each line of text in the file.

Listing 5 . Read and print the file contents with a while loop.
#Open the file object in default read mode. theFile = open("SampleTextFile.txt")#Read and print the lines of text using a different approach. line = theFile.readline()print(line,end='') while line != "":line = theFile.readline() print(line,end='')#Close the file theFile.close()

Figure 2 shows the output produced by the code in Listing 5 .

Figure 2 . Output from the code in Listing 5.
This is a sample text file. Second line of text.Third line. Fourth line.Last line. First appended line.Second appended line.

If you compare Figure 2 with Figure 1 , you will see that the two lines of text that were appended by the code in Listing 4 are shown in Figure 2 .

Run the program

I encourage you to copy the code from Listing 6 . Execute the code and confirm that you get the same results as those shown in Figure 3 . Experiment with the code, making changes, and observing the results of your changes. Make certain that youcan explain why your changes behave as they do.

Complete program listing

A complete listing of the program discussed in this module is provided in Listing 6 . The output produced by this program is shown in Figure 3 .

Listing 6 . Complete program listing.

# Illustrates how to write, read, and append to a text file. #---------------------------------------------------------------------------#Open a file object for writing. theFile = open("SampleTextFile.txt","w")#Write several lines of text to the file. Note the requirement to explicitly #provide the newline at the end of each line of text.theFile.write("This is a sample text file.\n") theFile.write("Second line of text.\n")theFile.write("Third line.\n") theFile.write("Fourth line.\n")theFile.write("Last line.\n") #Be sure to close the filetheFile.close() #Open the file object in read mode. Note that the "r" mode is the default#but it is shown here for clarity. theFile = open("SampleTextFile.txt","r")#Read and print the lines of text. for line in theFile:print(line,end='') #Close the filetheFile.close() print()#blank line to separate the output text#Append some text to the file. #Open the file object for appending.theFile = open("SampleTextFile.txt","a") #Append two more lines of text to the file.theFile.write("First appended line.\n") theFile.write("Second appended line.\n")#Close the file theFile.close()#Open the file object in default read mode. theFile = open("SampleTextFile.txt")#Read and print the lines of text using a different approach. line = theFile.readline()print(line,end='') while line != "":line = theFile.readline() print(line,end='')#Close the file theFile.close()
Figure 3 . Output produced by the code in Listing 6.
This is a sample text file. Second line of text.Third line. Fourth line.Last line. This is a sample text file.Second line of text. Third line.Fourth line. Last line.First appended line.


This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Itse1359-1510-Reading and Writing Text Files
  • File: Itse1359-1510.htm
  • Published: 10/28/14
  • Revised: 02/08/16

Financial : Although the Connexions site makes it possible for you to download a PDF file for thismodule at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, you should beaware that some of the HTML elements in this module may not translate well into PDF.

I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freely available on cnx.org and that it was made and published withoutmy prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.


Questions & Answers

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
Idrissa Reply
im all ears I need to learn
right! what he said ⤴⤴⤴
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
I'm not good at math so would you help me
what is the problem that i will help you to self with?
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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