In this article, we will discuss the topic of how to append in a python file.<\/p>\n
Before we fully understand this topic we have to be clear about some basic abbreviations that we use during file handling in python whether we have to write something to the file or append to the file.<\/p>\n
There are some modes in python that we need when we work with python files.<\/p>\n
These modes are:-<\/p>\n
So some may have a sort of confusion about what is the difference between appending and writing to a file. The basic difference between both of them is that when we open a file in write mode then as many as the time we perform write operation our original data will be overwritten with new data but when we access the file in append mode it means we append new data with original data.<\/p>\n
\u00a0<\/strong>As we know to perform any operation in a file first we have to access it.Here open() function comes into use.the open() function is used to open a file in reading or write or append mode. As our main concern in this topic is to discuss append data so we use append mode with the open() function.<\/p>\n the open() function takes two arguments first is the file name and another is the mode in which we want to access the file. If we do not pass any mode it will by default take \u2018r\u2019 mode.<\/p>\n So the syntax is open(fileName,mode).<\/p>\n To open files in append mode we use either \u2018a\u2019 mode or \u2018a+\u2019 mode. With file access mode \u2018a\u2019 open() function first checks if a file exists or not. If a file doesn\u2019t exist it creates a file and then opens it otherwise it directly opens the file. In both cases, a file object is returned.<\/p>\n Syntax: file_object=open(fileName,\u2019a\u2019). Or file_object=open(fileName,\u2019a+\u2019).<\/p>\n Here we can use any variable name. \u201cfile_object\u201d is not a compulsion. In file_object a file object is returned which is helpful to perform append operation in the file.<\/p>\n Here we see a word file object multiple times so let’s understand what file object actually means. The file object is the connector between us and the file. It allows us to read and write in the file. It takes a reference of the file and opens it in the different mode we want.<\/p>\n Example:<\/p>\n Input<\/p>\n Output<\/p>\n Note: \\n is used to append data to a new line otherwise our content will look like this\u2026<\/p>\n Output without using “\\n” is given below<\/p>\n We opened the file \u2018append_file.txt\u2019 in append mode i.e. using access mode \u2018a\u2019. As the cursor was pointing to the end of the file in the file object, therefore when we passed the string in the write() function, it appended it at the end of the file. So, our text \u2018Second\u00a0 Line\u2019 gets added at the end of the file \u2018append_file.txt\u2019.<\/p>\n In the previous example, we see that we use escape sequence \u2018\\n\u2019 to append data in a new line. This method is good but it will fail in one scenario. When a file does not exist or is empty then this approach will create a problem. Hence we should change this approach and work on a new approach that will work on all the cases.<\/p>\n Before understanding the new approach we must need to know about some abbreviations and functions.<\/p>\n For Example, if we write f.read(30) so it will read() first 30 characters from the file.<\/p>\n Note: If the file is only opened for writing in append mode using ‘a’, this method is essentially a no-op, but it remains useful for files opened in append mode with reading enabled (mode ‘a+’).<\/p>\n As we understand two important concepts now we will be comfortable in implementing the new approach to append data in a new line in the file.<\/p>\n Approach<\/p>\n As we check whether our file is empty or not so it will work on all the scenarios.<\/p>\n Examples Output<\/p>\n Before appending the string \u201csecond line\u201d in the file my file has the content \u201cHello Nice meeting you\u201d so it will append the second line\u201d in the new line.<\/p>\n With open() do similar functions as open() do but one difference is that we do not need to close files. with open() statement handles it.<\/p>\n Example<\/p>\n With open(file,a) as f is similar as f=open(file,a)<\/p>\n Input<\/p>\n Output<\/p>\n We clearly see that the output is the same as the previous one.<\/u><\/p>\nFile Object<\/h3>\n
f=open(\"append_file.txt\", \"a\")\r\nf.write(\"First Line\\n\")\r\nf.write(\"Second Line\")\r\nf.close()<\/pre>\n
First Line\r\n\r\nSecond Line<\/pre>\n
First LineSecond Line<\/pre>\n
Code Explanation<\/h3>\n
\u00a0Append Data to a new line in python files<\/h3>\n
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\nInput<\/p>\nf=open(\"append_file.txt\", \"a+\")\r\nf.seek(0)\r\ndata = f.read(100)\r\nif len(data) > 0 :\r\n f.write(\"\\n\")\r\nf.write(\"second line\")<\/pre>\n
Hello Nice meeting you\r\nsecond line<\/pre>\n
Use of with open statement to append text in the python file<\/h3>\n
with open(\"append_file.txt\",\"a\") as f:\r\n f.write(\"First Line\\n\")\r\n f.write(\"Second Line\")<\/pre>\n
First Line\r\n\r\nSecond Line<\/pre>\n
Appending List of items in the python file<\/h3>\n