On what basis should the merging take place? Your question is rather vague. Also, I assume a, b, …, f are supposed to be strings, that is, ‘a’, ‘b’, …, ‘f’. >>> x = [‘a’, ‘b’, ‘c’, ‘d’, ‘e’, ‘f’, ‘g’] >>> x[3:6] = [”.join(x[3:6])] >>> x [‘a’, ‘b’, ‘c’, ‘def’, ‘g’] Check out the … Read more
Every time you call append, Pandas returns a copy of the original dataframe plus your new row. This is called quadratic copy, and it is an O(N^2) operation that will quickly become very slow (especially since you have lots of data). In your case, I would recommend using lists, appending to them, and then calling … Read more
I think the use of StringBuilder vs + really depends on the context you are using it in. Generally using JDK 1.6 and above the compiler will automatically join strings together using StringBuilder. String one = “abc”; String two = “xyz”; String three = one + two; This will compile String three as: String three … Read more
test3 = pd.concat([test1, test2], axis=1) test3.columns = [‘a’,’b’] (But see the detailed answer by @feng-mai, below)
”.join(lst) The only Pythonic way: clear (that is what all the big boys do and what they expect to see), simple (no additional imports needed, and stable across all versions), fast (written in C) and concise (on an empty string, join elements of iterable!).
The xstr macro defined below will stringify after doing macro-expansion. #define xstr(a) str(a) #define str(a) #a #define RECORDS_PER_PAGE 10 #define REQUEST_RECORDS \ “SELECT Fields FROM Table WHERE Conditions” \ ” OFFSET %d * ” xstr(RECORDS_PER_PAGE) \ ” LIMIT ” xstr(RECORDS_PER_PAGE) “;”
Overcomplicated answers much? Here is my implementation: function TableConcat(t1,t2) for i=1,#t2 do t1[#t1+1] = t2[i] end return t1 end
As usual, the itertools module contains a solution: >>> l1=[1, 2, 3] >>> l2=[4, 5, 6] >>> l3=[7, 8, 9] >>> import itertools >>> list(itertools.chain(l1, l2, l3)) [1, 2, 3, 4, 5, 6, 7, 8, 9]
x = 1 y = “foo” + str(x) Please see the Python documentation: https://docs.python.org/3/library/functions.html#str