从python文件中读取列表格式的数据

Question

I know this must be a simple question for you all. I have textfile with test cases written in below list format,

[["arg1", "arg2", "arg3"], "Fail"]

[["arg1", "arg2", "arg4"], "Pass"]

. . .

And I want to read this file in a list such a that, I can print list1[1] => "Fail".

thanks for your help.

Answer 1

Assumptions

• You have a .txt file.
• Format of a line is [["arg1", "arg2", "arg3",...etc.], "Fail/Pass"]

Approach is to use regex to find all text between double quotes and append to the list. The last one is taken as "Fail/Pass" and rest of them are args.

import re

result = []

with open('text.txt','r') as f:
    for line in f:
        match = re.findall("\"(.*?)\"",line.strip())
        result.append([match[:-1],match[-1]])

print(result)
print(result[0][0])
print(result[0][1])

---

Sample Input .txt file

[["arg1", "arg2", "arg3","arg4"], "Fail"]
[["arg1", "arg2", "arg4"], "Pass"]

Output

[[['arg1', 'arg2', 'arg3', 'arg4'], 'Fail'], [['arg1', 'arg2', 'arg4'], 'Pass']]
['arg1', 'arg2', 'arg3', 'arg4']
Fail

Answer 2

Just use eval , its internal python function and you dont need libraries.

Example:

lists = []
line1 = '[["arg1", "arg2", "arg3"], "Fail"]'
line2 = '[["arg1", "arg2", "arg4"], "Pass"]'
# Evaluate Lines
exLine1 = eval(line1)
exLine2 = eval(line2)
# Append Lines to lists
lists.append(exLine1)
lists.append(exLine2)
# Testing Example of your use case
print(str(exLine1[1] == "Fail"))

Just Convert this example to for loop you are using and it will be fast and simple

Answer 3

You can use ast.literal_eval() to safe convert the string line to a python expression

Example:

import ast

with open('list.txt') as f:
    lines = f.readlines()

data = [ast.literal_eval(line) for line in lines]

for item in data:
    print(item[1])

Answer 4

I would do like this.

sample myfile.txt:

[["arg1", "arg2", "arg3"], "Fail"]
[["arg1", "arg2", "arg4"], "Pass"]

Main python file.

file1 = open('myfile.txt', 'r') 
count = 0

while True: 
    count += 1

    # Get next line from file 
    list = file1.readline()
    if not list: 
        break
    #convert string to list
    res = list.strip('][').split(', ') 
    print(res[1])

After reading the file line by line, Convert the string of list into list by using split.

Answer 5

You can hack together some pretty simple string manipulation code, as everyone is providing here. I've done it simply like this:

text = """
[["arg1", "arg2", "arg3"], "Fail"]
[["arg1", "arg2", "arg4"], "Pass"]
"""

for line in text.strip().splitlines():
    line = line.replace('[', '')
    line = line.replace(']', '')
    print line.split(',')[-1].strip()

It's not pretty but you can do it plenty of better ways if you're looking to do this is production.

Answer 6

you can try something like below:

with open("test.txt", "r") as test_file:
content = test_file.readlines()

print(content)
print(type(content))

for data in content:
    print(ast.literal_eval(data)[1])

print("*" * 30)
for i in range(1, len(content)+1):
    print(i)

output:

index:  0

[["arg1", "arg2", "arg3"], "Fail"]

index: 1

[["arg1", "arg2", "arg4"], "Pass"]

---

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Answer 7

What about this code example from link :

# load additional module
import pickle

with open('listfile.data', 'rb') as filehandle:
    # read the data as binary data stream
    placesList = pickle.load(filehandle)