I have a file and its consist of multiple lists like below
[234,343,234]
[23,45,34,5]
[354,45]
[]
[334,23]
I am trying to read line by line and append to a single list in python.
how to do it?
I tried so far>
with open("pos.txt","r") as filePos:
pos_lists=filePos.read()
new_list=[]
for i in pos_lists.split("\n"):
print(type(i)) #it is str i want it as list
new_list.extend(i)
print(new_list)
thanks in advance
You can try these:
>>> from ast import literal_eval
>>> with open(YOURTEXTFILE) as f:
... final_list = [literal_eval(elem) for elem in f.readlines()]
>>> final_list
[[234, 343, 234], [23, 45, 34, 5], [354, 45], [], [334, 23]]
Or,
>>> from ast import literal_eval
>>> with open(YOURTEXTFILE) as f:
... final_list = sum(map(literal_eval, s.readlines()), [])
>>> final_list
[234, 343, 234, 23, 45, 34, 5, 354, 45, 334, 23]
Whichever you want.
The same thing can be done with python built-in eval() however, it is not recommended to use eval() on untrusted code, instead use ast.literal_eval() which only works on very limited data types.
For more on this, see Using python's eval() vs. ast.literal_eval()?
You can use ast.literal_eval
>>> res = []
>>> with open('f.txt') as f:
... for line in f:
... res.append(ast.literal_eval(line))
If the lines are assumed and intended to be python literals you can just ast.literal_eval(line).
For safety you may want to assume they are JSON values instead, in which case json.loads(line) should do the trick.
In case each line is a valid JSON array/object, you can use jsonlines:
import jsonlines
r = []
with jsonlines.open('input.jsonl') as reader:
for line in reader:
for item in line:
r.append(item)
print(r)
Output:
[234, 343, 234, 23, 45, 34, 5, 354, 45, 334, 23]
you can use the split() method between the brackets you can give a symbol to split by.
between the brackets give the symbol you want to split it by. Maybe like this:
txt = "[234,343,234]/[23,45,34,5]/[354,45]/[]/[334,23]"
x = txt.split("/")
