将 python 列表划分为嵌套列表

Question

Hello python enthusiasts.! I have a text file with content like this.

Pakistan[country]\n
Karachi\n
lahore\n
islamabad\n
UAE[country]\n
dubai\n
sharjah\n
India[country]\n
goa\n
chennai\n

I read this file using this code.

mylist = list(open('data.txt', 'r'))

now i have all of elements in list structure, but i want to transform this into a nested list, a list structure like below.

[['Pakistan', 'Karachi', 'lahore', 'islamabad'],['UAE', 'dubai', 'sharjah'],['India', 'goa', 'chennai']]

Kindly help me to transform this text into above structure.

Answer 1

Here you go:

>>> result = []
>>> for entry in mylist:
        if entry.endswith('[country]'):
            country= entry[:entry.rindex('[')]
            result.append([country])
        else:
            result[-1].append(entry)


>>> result
[['Pakistan', 'Karachi', 'lahore', 'islamabad'], ['UAE', 'dubai', 'sharjah'], ['India', 'goa', 'chennai']]

Answer 2

You can do something like this.

results = []
tmp =[]
with open("data.txt", "r") as file:
    for line in file:
        if "country" in line:
            if tmp:
                results.append(tmp)
             tmp = []
             line = line.replace("[country]", "")
        tmp.append(line.strip())
     results.append(tmp)
print(results)   

Answer 3

mylist = list(open('data.txt', 'r')) superlist = [] countrylist = [] for entry in mylist: if '[country]' in entry: superlist.append(countrylist) countrylist = [entry.replace('[country]', '')] else: countrylist.append(entry) if len(countrylist) > 0: superlist.append(countrylist)

Answer 4

temp = StringIO("""  
Pakistan[country]\n
Karachi\n
lahore\n
islamabad\n
UAE[country]\n
dubai\n
sharjah\n
India[country]\n
goa\n
chennai\n
""")


df = pd.read_csv(temp, sep='\s+', engine='python',header=None)

---

using re.split

 country_l = ' '.join(list(df[0])) [i.replace('[country]','').split() for i in re.split('\s(?=\w*\[country\])',country_l)] ##output [['Pakistan', 'Karachi', 'lahore', 'islamabad'], ['UAE', 'dubai', 'sharjah'], ['India', 'goa', 'chennai']]

Answer 5

my_list = list(open('data.txt', 'r'))    
j = -1
for country in my_list:
    if country.__contains__('[country]'):
        country = country[:country.find('[country]')]
        result.append([country])
        j += 1
    else:
        country = country[:country.find('\n')]
        result[j].append(country)

Answer 6

Disclaimer: this solution is not for the faint-hearted, and does not really prioritize readability.

I'm a little intrigued that none of the currently posted answers solves this issue by .split("[country]") . Here is a solution by list comprehensions:

 # read file this way to preserve line structure:
 with open('data.txt', 'r') as f:
     data = f.read().strip().split("\n")

 # First: move the "[country]" tag from behind to in front of the name.
 # Also, I replace "[country]" with "*" for no other reason than that it's shorter
 data = ",".join(["*"+x.replace("[country]","") if x.endswith("[country]") else x for x in data])

 # Then, split on "[country]", that is: ",*",
 # But keep in mind that the very first country will have prefix "*", not ",*"
 data = [x.replace("*","").split(",") for x in data.split(",*")]

 print(data)
 #[['Pakistan', 'Karachi', 'lahore', 'islamabad'], ['UAE', 'dubai', 'sharjah'], ['India', 'goa', 'chennai']]

Another, much cleaner approach if you're able to change the format of your data file such that the tag [country] is set in front of the country name instead of after, then it is a little simpler, and you'll get away with a simple one-liner:

 with open('data2.txt', 'r') as f:
     data = f.read().strip().split("[country]")

 data = [x.strip().replace("[country]","").split("\n") for x in data[1:]]

 print(data)
 #[['Pakistan', 'Karachi', 'lahore', 'islamabad'], ['UAE', 'dubai', 'sharjah'], ['India', 'goa', 'chennai']]