Dec 14, 2010 · If you only have one reference to a string and you concatenate another string to the end, CPython now special cases this and tries to extend the string in place. The end result is that the operation is amortized O(n). e.g. s = "" for i in range(n): s += str(i) used to be O(n^2), but now it is O(n). More information. From the source (bytesobject.c):

Nov 17, 2013 · The f-string version is almost as fast as @RomanPekar's solution (python 3.6.4): df = pd.DataFrame({'col':['a', 0]*200000}) %timeit df['col'].apply(lambda x: f"str{x}") 117 ms ± 451 µs per loop (mean ± std. dev. of 7 runs, 10 loops each) %timeit 'str' + df['col'].astype(str) 112 ms ± 1.04 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)

If you are using python 3.6 and newer then you can use f-strings to do the task like this. print(f"I have {card.price}") just include f in front of your string and add the variable inside curly braces { }. Refer to a blog The new f-strings in Python 3.6: written by Christoph Zwerschke which includes execution times of the various method.

Sep 17, 2012 · The result of join is always a string, but the object to be joined can be of many types (generators, list, tuples, etc)..join is faster because it allocates memory only once. Better than classical concatenation (see, extended explanation). Once you learn it, it's very comfortable and you can do tricks like this to add parentheses.

The simplest thing is to use python's triple quotes (note the three single quotes) stringtowrite = '''abcd || efgh|| iklk''' any string literal with triple quotes will continue on a following line. You can use ''' or """. By the way, if you have. a = abcd b = efgh c = iklk I would recommend the following:

For ordinary functions and methods, like input, or the savefig method of Matplotlib plots, we need to prepare a string ourselves. Concatenation. Python supports using + between two strings, but not between strings and other types. To work around this, we need to convert other values to string explicitly: 'hanning' + str(num) + '.pdf'.

See Format String Syntax for a description of the various formatting options that can be specified in format strings. This method of string formatting is the new standard in Python 3.0, and should be preferred to the % formatting described in String Formatting Operations in new code. New in …

Oct 15, 2020 · Running the following experiment the pythonic way: [s + mystring for s in mylist] seems to be ~35% faster than the obvious use of a for loop like this:

Apr 8, 2012 · Strings are immutable so you can't insert characters into an existing string. You have to create a new string. You can use string concatenation to do what you want: yourstring = "L" + yourstring + "LL" Note that you can also create a string with n Ls by using multiplication: m = 1 n = 2 yourstring = ("L" * m) + yourstring + ("L" * n)

Nov 10, 2018 · Python add string value between variables conditonally. 0. Add a character in a string inside a column ...