In this post we’ve taken an in-depth look at how to clear text files in Python. Lastly, we’ll need to open the file and read it to prove that the file was handled correctly. Next, we’ll write the data to a new file, clearing the lines we don’t want. To begin, we’ll open the file to extract its contents. In this example, we need to open the file three times.
If the string we’re looking for is in the line, we can avoid including it in the output file. What if we want to remove a line from a string that contains a certain word, phrase, or number? We can use a Python if statement to check the string data of each line. Output What happens to a dream deferred? How to Clear a Text File Using a String Using these tools offers plenty of versatility when it comes to creating subsets of lists. It’s also possible to combine sliced lists. Using this method of overwriting the original file, we can effectively clear the file of any unwanted data.īy changing the start and end indexes of the slice, we’ll get a different subset of the dream.txt file. With slice notation, we can create any subset of the data we want. It’s also possible to remove more than one line of text from a file. Using slice notation, it’s possible to omit the first line of the original file. Thirdly, we’ll write a new list of lines to the file. Secondly, we can use the truncate() method to resize the file. With the seek() method, we can manually reposition the file pointer. Firstly, we’ll use readlines() to get a list of the file’s text data. In order to clear the first line of text from a file, we’ll need to use a few of Python’s file handling methods. Like a raisin in the sun? Clear the First Line of a Text File The following examples use an excerpt from the poem “Dream Deferred” by the American writer Langston Hughes. In that case, we can use slice notation to retrieve a subset of the file.īy writing over a file with a subset of its data, we can remove lines of text. It’s especially helpful if we know which lines we want to remove ahead of time. Using some common Python functions, we can also clear specific lines of data from text files. How to Delete Specific Lines from a Text File Output Guido van Rossum created Python in 1991. The others will be cleared from the text file. The readlines() method will return a list of the lines of text in the document.Īfter the lines are extracted, we can use slice notation to create a new list that we’ll use to overwrite the old file. Next, we’ll use the same info.txt document from the previous section to demonstrate how slice notation can be used to clear lines from a text file. By defining the start, end, and step of the slice, we’ll obtain a subset of the original list. The following example shows how slice notation works. Slice notation uses a special syntax to find a subset of a range of values. Using this Python feature, we can define the start and end indexes of a given subset. With Python slice notation, it’s possible to retrieve a subset of a list, string, or tuple.
Clear a Text File Using Python List Slicing Using the truncate() method in this manner will reduce the file size to 0, erasing any content the file contained.
Simple clean text code#
The above Python code will clear a text file of it’s content. This is necessary in order for the truncate method to work.īy passing a value of 0 to the truncate() method, it’s possible to clear the text file completely. Notice that we opened the file in both read and write mode. In the above example, the truncate() method reduced the file to the first 16 characters of text. One of Python’s strengths is readability. Python is a general purpose programming language. We’ll use a demo text file to test Python’s capabilities for truncating files: For example, the program may add white space to the end of the file if the truncate size exceeds the original file size. If no argument is supplied, the file is left unchanged.Īn attempt to truncate a file to longer than its original size may have unexpected results. This method takes an optional argument that sets the new size of the file. The truncate() method reduces a document’s size. How to Clear a File with the truncate() Method Using with to open a file in write mode will also clear its data. The Python with statement simplifies exception handling. The simplest way to delete a file is to use open() and assign it to a new variable in write mode. Also, if the file specified doesn’t exist, Python will create a new one. Opening a file in write mode clears its data. The open() function takes two arguments, the text file we’d like to open and the mode we’re opening it in. Opening a file in write mode will automatically delete the file’s contents. Clear a Text File Using the open() Function in write Mode
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