Lots of other answers here, but to answer precisely the question you asked (before @MarkAmery went and edited the original question and changed the meaning): Show
In other words, if you've already read in the file (as you said), and have a big block of data in memory, then to get the first line from it efficiently, do a split() on the newline character, once only, and take the first element from the resulting list. Note that this does not include
the Created: January-18, 2021 In Python,
we have built-in functions that can handle different file operations. A Text file contains a sequence of strings in which every line terminated using a newline character In this tutorial, we will learn how to read the first line of a text file in Python. We can use the The Output: Another method to read the first line of a file is using the Output: Notice that we use the We can also use the
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Use the next() Function to Read the First Line of a File in PythonAn unconventional method of achieving the same is by using the
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Related Article - Python FileView Discussion Improve Article Save Article View Discussion Improve Article Save Article Text files are composed of plain text content. Text files are also known as flat files or plain files. Python provides easy support to read and access the content within the file. Text files are first opened and then the content is accessed from it in the order of lines. By default, the line numbers begin with the 0th index. There are various ways to read specific lines from a text file in python, this article is aimed at discussing them. File in use: test.txt Method 1: fileobject.readlines() A file object can be created in Python and then readlines() method can be invoked on this object to read lines into a stream. This method is preferred when a single line or a range of lines from a file needs to be accessed simultaneously. It can be easily used to print lines from any random starting index to some ending index. It initially reads the entire content of the file and keep a copy of it in memory. The lines at the specified indices are then accessed. Example: Python3
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Method 2: linecache package The linecache package can be imported in Python and then be used to extract and access specific lines in Python. The package can be used to read multiple lines simultaneously. It makes use of cache storage to perform optimization internally. This package opens the file on its own and gets to the particular line. This package has getline() method which is used for the same. Syntax: getLine(txt-file, line_number) Example: Python3
Output : This is line 5. Method 3: enumerate() The enumerate() method is used to convert a string or a list object to a sequence of data indexed by numbers. It is then used in the listing of the data in combination with for loop. Lines at particular indexes can be accessed by specifying the index numbers required in an array. Example: Python3
Output This is line 1. This is line 8. This is line 12. How do I read the first few lines of a file in Python?Use file.. a_file = open("file_name.txt") Open "file_name.txt". number_of_lines = 3.. for i in range(number_of_lines): Print the first number_of_lines lines of a_file.. line = a_file. readline(). print(line). How do I read the first and last line of a file in Python?Use file. readline() to read a single line from a file
readline() to get the first line of the file and store this in a variable first_line . Create a second variable, last_line , and iterate through all lines in the file until the end. Once the iteration ends, last_line will contain the last line of the file.
How do I read a specific part of a file in Python?Method 1: fileobject.readlines()
A file object can be created in Python and then readlines() method can be invoked on this object to read lines into a stream. This method is preferred when a single line or a range of lines from a file needs to be accessed simultaneously.
How do you read a line from a text file in Python?To read a text file in Python, you follow these steps: First, open a text file for reading by using the open() function. Second, read text from the text file using the file read() , readline() , or readlines() method of the file object.
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1) open() function.. |