{"id":38006,"date":"2016-10-14T17:34:55","date_gmt":"2016-10-14T22:34:55","guid":{"rendered":"http:\/\/danigguemez.wordpress.com\/?p=458"},"modified":"2016-10-14T17:34:55","modified_gmt":"2016-10-14T22:34:55","slug":"files-in-python","status":"publish","type":"post","link":"https:\/\/kenscourses.com\/tc101fall2016\/syndicated\/files-in-python\/","title":{"rendered":"Files in Python"},"content":{"rendered":"

--Originally published at Fundamentos de Programaci\u00f3n<\/a><\/a><\/em>
<\/p>\n

In the blog about counting words, I used the funtion open() to coun the words in that file but I haven’t made a post explaining how to do that, so here it is:<\/p>\n

In Python, you don’t need to import any library to read and write files.<\/p>\n

The first step is to get a file object.<\/p>\n

The way to do this is to use the open function.<\/p>\n

A file is usually categorized as either text or binary.<\/p>\n

\"vmveq3w_700wa_0\"<\/p>\n

A text file is often structured as a sequence of lines and a line is a sequence<\/p>\n

of characters.<\/p>\n

The line is terminated by a EOL (End Of Line) character.<\/p>\n

The backslash character indicates that the next character will be treated as a<\/p>\n

newline.<\/p>\n

A binary file is basically any file that is not a text file. Binary files can<\/p>\n

only be processed by application that know about the file’s structure.<\/p>\n

To open a file for writing use the built-i open() function. open() returns a<\/p>\n

file object, and is most commonly used with two arguments.<\/p>\n

 <\/p>\n

The syntax is:<\/p>\n

file_object = open(filename, mode) where file_object is the variable to put the<\/p>\n

file object.<\/p>\n

 <\/p>\n

The second argument describes the way in which the file will be used<\/p>\n

The mode argument is optional; ‘r’ will be assumed if it\u2019s omitted.<\/p>\n

\"lmzjvmm_700w_0\"<\/p>\n

The modes can be:<\/p>\n

‘r’ when the file will only be read<\/p>\n

‘w’ for only writing (an existing file with the same name will be erased)<\/p>\n

‘a’ opens the file for appending; any data written to the file is automatically<\/p>\n

added to the end.<\/p>\n

‘r+’ opens the file for both reading and writing.<\/p>\n

\"ymkd7rq_700wa_0\"<\/p>\n

Create a text file<\/strong><\/p>\n

Let’s first create a new text file. You can name it anything you like,<\/p>\n

in this example we will name it “newfile.txt”.<\/p>\n

file = open(“newfile.txt”,

\"\"<\/div>\n
\"\"<\/div><\/p>\n

file.write(“hello world in the new file<\/p>\n

“)<\/p>\n

file.write(“and another line<\/p>\n

“)<\/p>\n

file.close()<\/p>\n

How to read a text file<\/strong><\/p>\n

To read a file, we can use different methods.<\/p>\n

file.read( )<\/p>\n

If you want to return a string containing all characters in the file, you can<\/p>\n

use file.read().<\/p>\n

file = open(‘newfile.txt’, ‘r’)<\/p>\n

print file.read()<\/p>\n

Output:<\/p>\n

hello world in the new file<\/p>\n

and another line<\/p>\n

A video that explains it:<\/p>\n