Square brackets are lists while parentheses are tuples. A list is mutable, meaning you can change its contents: >>> x = [1,2] >>> x.append(3) >>> x [1, 2, 3] while tuples are not: >>> x = (1,2) >>> x (1, 2) >>> x.append(3) Traceback (most recent call last): File “<stdin>”, line 1, in <module> AttributeError: … Read more
Get comfortable with zip. It comes in handy when dealing with column data. df[‘new_col’] = list(zip(df.lat, df.long)) It’s less complicated and faster than using apply or map. Something like np.dstack is twice as fast as zip, but wouldn’t give you tuples.
You need to make the second element a 1-tuple, eg: a = (‘2’,) b = ‘z’ new = a + (b,)
lst1, lst2 = zip(*zipped_list) should give you the unzipped list. *zipped_list unpacks the zipped_list object. it then passes all the tuples from the zipped_list object to zip, which just packs them back up as they were when you passed them in. so if: a = [1,2,3] b = [4,5,6] then zipped_list = zip(a,b) gives you: … Read more
Tuples are compared position by position: the first item of the first tuple is compared to the first item of the second tuple; if they are not equal (i.e. the first is greater or smaller than the second) then that’s the result of the comparison, else the second item is considered, then the third and … Read more
You can use the str.split method. >>> my_string = ‘A,B,C,D,E’ >>> my_list = my_string.split(“,”) >>> print my_list [‘A’, ‘B’, ‘C’, ‘D’, ‘E’] If you want to convert it to a tuple, just >>> print tuple(my_list) (‘A’, ‘B’, ‘C’, ‘D’, ‘E’) If you are looking to append to a list, try this: >>> my_list.append(‘F’) >>> print … Read more
>>> source_list = [(‘1′,’a’),(‘2′,’b’),(‘3′,’c’),(‘4′,’d’)] >>> list1, list2 = zip(*source_list) >>> list1 (‘1’, ‘2’, ‘3’, ‘4’) >>> list2 (‘a’, ‘b’, ‘c’, ‘d’) Edit: Note that zip(*iterable) is its own inverse: >>> list(source_list) == zip(*zip(*source_list)) True When unpacking into two lists, this becomes: >>> list1, list2 = zip(*source_list) >>> list(source_list) == zip(list1, list2) True Addition suggested by … Read more
Convert tuple to list: >>> t = (‘my’, ‘name’, ‘is’, ‘mr’, ‘tuple’) >>> t (‘my’, ‘name’, ‘is’, ‘mr’, ‘tuple’) >>> list(t) [‘my’, ‘name’, ‘is’, ‘mr’, ‘tuple’] Convert list to tuple: >>> l = [‘my’, ‘name’, ‘is’, ‘mr’, ‘list’] >>> l [‘my’, ‘name’, ‘is’, ‘mr’, ‘list’] >>> tuple(l) (‘my’, ‘name’, ‘is’, ‘mr’, ‘list’)
Use zip(*list): >>> l = [(1,2), (3,4), (8,9)] >>> list(zip(*l)) [(1, 3, 8), (2, 4, 9)] The zip() function pairs up the elements from all inputs, starting with the first values, then the second, etc. By using *l you apply all tuples in l as separate arguments to the zip() function, so zip() pairs up … Read more
In C# 7.0 (Visual Studio 2017) there is a new construction to do that: (string first, string middle, string last) LookupName(long id)