Searching text file python

This module offers classes representing filesystem paths with semantics appropriate for different operating systems. To replace the text using pathlib2 module we will use the Path method of pathlib2 module. We are going to use the re. Syntax: re.

Skip to content. Change Language. Related Articles. Table of Contents. Improve Article. Save Article. Like Article. Opening our text file in read only.

Reading the content of the file. Searching and replacing the text. But would have been really nice if you had provided the code with proper indentation. Save my name, email, and website in this browser for the next time I comment. Sign in. Forgot your password? Get help. Privacy Policy. Password recovery. Open Source For You. The Latest Trends in the Programming World.

Elixir: Made for Building Scalable Applications. Eclipse in Action. Simplify Invoicing by Creating a Template with Python. Building Reusable Modules. Online Anonymity with Tor. Top 5 Open Source Firewalls. SecureDrop: Making Whistleblowing Possible. We can print the first element of lines by specifying index number 0 , contained in brackets after the name of the list:. A list object is an iterator, so to print every element of the list, we can iterate over it with for But we're still getting extra newlines.

Also, after printing each line, print adds a newline of its own, unless you tell it to do otherwise. We can change this default behavior by specifying an end parameter in our print call:. By setting end to an empty string two single quotes, with no space , we tell print to print nothing at the end of a line, instead of a newline character. We want to get rid of these, so we don't have to worry about them while we process the file.

To remove the newlines completely, we can strip them. To strip a string is to remove one or more characters, usually whitespace , from either the beginning or end of the string. Python 3 string objects have a method called rstrip , which strips characters from the right side of a string.

The English language reads left-to-right, so stripping from the right side removes characters from the end. If the variable is named mystring , we can strip its right side with mystring. For example, "abc". When you represent a string in your program with its literal contents, it's called a string literal. In Python as in most programming languages , string literals are always quoted — enclosed on either side by single ' or double " quotes.

In Python, single and double quotes are equivalent; you can use one or the other, as long as they match on both ends of the string. It's traditional to represent a human-readable string such as Hello in double-quotes "Hello". For more information about how to use strings in Python, you can read the documentation of strings in Python.

The statement string. The following version of our program strips the newlines when each line is read from the text file:. The text is now stored in a list variable, so individual lines can be accessed by index number.

Newlines were stripped, so we don't have to worry about them. We can always put them back later if we reconstruct the file and write it to disk. Now, let's search the lines in the list for a specific substring. Let's say we want to locate every occurrence of a certain phrase, or even a single letter. For instance, maybe we need to know where every "e" is. We can accomplish this using the string's find method.

The list stores each line of our text as a string object. All string objects have a method, find , which locates the first occurrence of a substrings in the string. Let's use the find method to search for the letter "e" in the first line of our text file, which is stored in the list mylines. The first element of mylines is a string object containing the first line of the text file.

This string object has a find method. In the parentheses of find , we specify parameters. The first and only required parameter is the string to search for, "e". The statement mylines[0].

If it reaches the end of the string, it returns -1 to indicate nothing was found. The return value "3" tells us that the letter "e" is the fourth character, the "e" in "Lorem".

Remember, the index is zero-based: index 0 is the first character, 1 is the second, etc. MongoDB tutorials. Privacy Policy. Python Introduction.

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