How to Convert List to String

Column of lists, convert list to string as a new column

List Comprehension

If performance is important, I strongly recommend this solution and I can explain why.

df['liststring'] = [','.join(map(str, l)) for l in df['lists']]
df

                lists    liststring
0  [1, 2, 12, 6, ABC]  1,2,12,6,ABC
1     [1000, 4, z, a]    1000,4,z,a

You can extend this to more complicated use cases using a function.

def try_join(l):
    try:
        return ','.join(map(str, l))
    except TypeError:
        return np.nan

df['liststring'] = [try_join(l) for l in df['lists']]

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Series.apply/Series.agg with ','.join

You need to convert your list items to strings first, that's where the map comes in handy.

df['liststring'] = df['lists'].apply(lambda x: ','.join(map(str, x)))

Or,

df['liststring'] = df['lists'].agg(lambda x: ','.join(map(str, x)))

<!- >

df
                lists    liststring
0  [1, 2, 12, 6, ABC]  1,2,12,6,ABC
1     [1000, 4, z, a]    1000,4,z,a

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pd.DataFrame constructor with DataFrame.agg

A non-loopy/non-lambda solution.

df['liststring'] = (pd.DataFrame(df.lists.tolist())
                      .fillna('')
                      .astype(str)
                      .agg(','.join, 1)
                      .str.strip(','))

df
                lists    liststring
0  [1, 2, 12, 6, ABC]  1,2,12,6,ABC
1     [1000, 4, z, a]    1000,4,z,a

How to convert String List to String in flutter?

You can iterate list and concatenate values with StringBuffer

  var list = ['one', 'two', 'three'];
  var concatenate = StringBuffer();

  list.forEach((item){
    concatenate.write(item);
  });

  print(concatenate); // displays 'onetwothree'

  }

Convert list to string using python

Firstly convert integers to string using strusing map function then use join function-

>>> ','.join(map(str,[10,"test",10.5]) )#since added comma inside the single quote output will be comma(,) separated
>>> '10,test,10.5'

Or if you want to convert each element of list into string then try-

>>> map(str,[10,"test",10.5])
>>> ['10', 'test', '10.5']

Or use itertools for memory efficiency(large data)

>>>from itertools import imap
>>>[i for i in imap(str,[10,"test",10.5])]
>>>['10', 'test', '10.5']

Or simply use list comprehension

>>>my_list=['10', 'test', 10.5]
>>>my_string_list=[str(i) for i in my_list]
>>>my_string_list
>>>['10', 'test', '10.5']

Convert a list to a string and back

JSON!

import json

with open(data_file, 'wb') as dump:
    dump.write(json.dumps(arbitrary_data))

and similarly:

source = open(data_file, 'rb').read()
data = json.loads(source)

Convert a list of strings to a single string

string Something = string.Join(",", MyList);

How to convert list to string and how to save for loop result into variable in python?

''.join(list_of_strings)

best advise I ever got..

for your case:

string = "3,9,13,4,42"

lista = [int(i) for i in string.split(',')]
list_of_strings = []

for i in lista:
   list_of_strings.append(str(i**2))  # appending each value as a string in list 
string = ",".join(list_of_strings)  # the "," will add comma between each values in the list.

Converting List String to String[] in Java

You want

String[] strarray = strlist.toArray(new String[0]);

See here for the documentation and note that you can also call this method in such a way that it populates the passed array, rather than just using it to work out what type to return. Also note that maybe when you print your array you'd prefer

System.out.println(Arrays.toString(strarray));

since that will print the actual elements.

How can I convert a list to a string in Terraform?

Conversion from list to string always requires an explicit decision about how the result will be formatted: which character (if any) will delimit the individual items, which delimiters (if any) will mark each item, which markers will be included at the start and end (if any) to explicitly mark the result as a list.

The syntax example you showed looks like JSON. If that is your goal then the easiest answer is to use jsonencode to convert the list directly to JSON syntax:

jsonencode(var.names)

This function produces compact JSON, so the result would be the following:

["ben","linda","john"]

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Terraform provides a ready-to-use function for JSON because its a common need. If you need more control over the above decisions then you'd need to use more complex techniques to describe to Terraform what you need. For example, to produce a string where each input string is in quotes, the items are separated by commas, and the entire result is delimited by [ and ] markers, there are three steps:

• Transform the list to add the quotes: [for s in var.names : format("%q", s)]
• Join that result using , as the delimiter: join(", ", [for s in var.names : format("%q", s)])
• Add the leading and trailing markers: "[ ${join(",", [for s in var.names : format("%q", s)])} ]"

The above makes the same decisions as the JSON encoding of a list, so there's no real reason to do exactly what I've shown above, but I'm showing the individual steps here as an example so that those who want to produce a different list serialization have a starting point to work from.

For example, if the spaces after the commas were important then you could adjust the first argument to join in the above to include a space:

"[ ${join(", ", [for s in var.names : format("%q", s)])} ]"

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