Text Files
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Text files store data in text form only.
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They use ASCII or Unicode characters.
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Each line ends with EOL (End of Line) — usually
\n. -
To work on a file: open → write → save → close.
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You can also open an existing file to read or edit data.
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Same method is used in File Handling / Data File Handling.
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Example:
notes.txtordata.txt
- Reading from a File
Methods to Read: It includes three function to read which are given as under with example.
| Method | Description |
|---|---|
1. read() |
Reads entire file content as a string. |
2. readline() |
Reads one line at a time. |
3. readlines() |
Reads all lines into a list. |
Examples:
1. read( )
f = open("data.txt", "r")
print(f.read()) # entire file
f.close()
2. readline ( )
f = open("data.txt", "r")
print(f.readline()) # one line
f.close()
3. readlines ( )
f = open("data.txt", "r")
print(f.readlines()) # list of lines
f.close()
- Writing to a File
Methods to Write: It includes two function to write, which are given as under with example. Both methods are used to write data into a text file
1. Using write() method:
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Used to write a single string into a file.
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It overwrites existing content if the file is opened in
'w'mode. -
No automatic newline (
\n) is added — you must add it manually.
f = open("data.txt", "w")
f.write("Hello, this is a file handling example.")
f.close()
2. Using writelines() method:
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Used to write multiple lines (list or tuple of strings) into a file.
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It writes all strings together — doesn’t add
\nautomatically. -
You must include
\nin each string manually if you want new lines.
lines = ["Line1\n", "Line2\n", "Line3\n"]
f = open("data.txt", "w")
f.writelines(lines)
f.close()
Difference between write() and writelines()-
| Feature | write () |
writelines() |
|---|---|---|
| Data type | Single string | List or tuple of strings |
Newline (\n) |
Must add manually | Must add manually |
| Writes | One string at a time | Multiple strings at once |
| Example | f.write("Hello\n") |
f.writelines(["A\n", "B\n"]) |
- Appending to a File
Methods to Appending-
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Appending means adding new data at the end of an existing file without deleting old data.
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In Python, this is done using the
'a'mode in theopen()function. -
If the file already exists, new data is added at the end.
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If the file does not exist, Python creates a new file.
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Old data is not erased (unlike
'w'mode). -
Cursor always stays at end of file when opened in
'a'mode.
#using write function
f = open("data.txt", "a")
f.write("\nThis is new data added at the end.")
f.close()
# using writelines function
f = open("data.txt", "a")
lines = ["\nLine 3", "\nLine 4"]
f.writelines(lines)
f.close()
