How to read a text file into a list in Python
How to read a text file into a list in Python
The
contents of a file are a sequence of characters. The characters are
interpreted as a list of values by splitting on a delimiter. For
example, a comma-separated values (CSV) file with the content "1,2,3" split on the delimiter "," creates the list ["1", "2", "3"].
Use str.split() to split a text file into a list
Call file.read() to return the entire content of file as a string. Call str.split(sep) with this string as str to return a list of the values of the file split by sep.
```
my_file = open("sample.txt", "r")content = my_file.read()print(content)```
Output
1,2,3``` content_list = content.split(",")my_file.close()print(content_list)```
Output
['1', '2', '3']Use file.readlines() to read a text file into a list
Call file.readlines() to return a list where each item is a line from file.
```my_file = open("sample.txt", "r")content_list = my_file.readlines()print(content_list)```
Output
['1\n', '2\n', '3\n']Warning: If the entire content of the file is all on one line,
file.readlines()will return a list containing one item instead of a list of individual items.
When our input lists are contain \n, we need to remove it and converting as a list. so, we can use below code
content_list =
[1\n2\n3\n] #input
```
content_list = content.split("\n")
# we are splitting a value and converting as a list in a required format
my_file.close()
print(content_list)
```
Output
['1', '2', '3']How to save getting list values in a text file
```
#values = ['1', '2', '3']
content_list # Previously getting output list, we are using here
with open("filename.txt", "w") as output:
output.write(str(content_list))
```
Also, we can go with alternative method using json
```
```
import json
a = [1,2,3]
with open('test.txt', 'w') as f:
f.write(json.dumps(a))
#Now read the file back into a Python list object
with open('test.txt', 'r') as f:
a = json.loads(f.read())
```
References - Building the future with software
link - https://www.adamsmith.haus/python/
link - https://www.adamsmith.haus/python/
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