Algorithm To generate a random string, concatenate characters drawn randomly from the set of acceptable symbols until the string reaches the desired length. Implementation Here’s some fairly simple and very flexible code for generating random identifiers. Read the information that follows for important application notes. public class RandomString { /** * Generate a random string. … Read more
To pad strings: >>> n = ‘4’ >>> print(n.zfill(3)) 004 To pad numbers: >>> n = 4 >>> print(f'{n:03}’) # Preferred method, python >= 3.6 004 >>> print(‘%03d’ % n) 004 >>> print(format(n, ’03’)) # python >= 2.6 004 >>> print(‘{0:03d}’.format(n)) # python >= 2.6 + python 3 004 >>> print(‘{foo:03d}’.format(foo=n)) # python >= 2.6 … Read more
Empty strings are “falsy” (python 2 or python 3 reference), which means they are considered false in a Boolean context, so you can just do this: if not myString: This is the preferred way if you know that your variable is a string. If your variable could also be some other type then you should … Read more
C++11 introduces std::stoi (and variants for each numeric type) and std::to_string, the counterparts of the C atoi and itoa but expressed in term of std::string. #include <string> std::string s = std::to_string(42); is therefore the shortest way I can think of. You can even omit naming the type, using the auto keyword: auto s = std::to_string(42); … Read more
It’s because any iterable can be joined (e.g, list, tuple, dict, set), but its contents and the “joiner” must be strings. For example: ‘_’.join([‘welcome’, ‘to’, ‘stack’, ‘overflow’]) ‘_’.join((‘welcome’, ‘to’, ‘stack’, ‘overflow’)) ‘welcome_to_stack_overflow’ Using something other than strings will raise the following error: TypeError: sequence item 0: expected str instance, int found
This code will read the entire file into memory and remove all whitespace characters (newlines and spaces) from the end of each line: with open(filename) as file: lines = file.readlines() lines = [line.rstrip() for line in lines] If you’re working with a large file, then you should instead read and process it line-by-line: with open(filename) … Read more
The simplest way would be to use the native Number function: var x = Number(“1000”) If that doesn’t work for you, then there are the parseInt, unary plus, parseFloat with floor, and Math.round methods. parseInt: var x = parseInt(“1000”, 10); // you want to use radix 10 // so you get a decimal number even … Read more
You need to double the {{ and }}: >>> x = ” {{ Hello }} {0} ” >>> print(x.format(42)) ‘ { Hello } 42 ‘ Here’s the relevant part of the Python documentation for format string syntax: Format strings contain “replacement fields” surrounded by curly braces {}. Anything that is not contained in braces is … Read more
The most likely reason for use of single vs. double in different libraries is programmer preference and/or API consistency. Other than being consistent, use whichever best suits the string. Using the other type of quote as a literal: alert(‘Say “Hello”‘); alert(“Say ‘Hello'”); This can get complicated: alert(“It’s \”game\” time.”); alert(‘It\’s “game” time.’); Another option, new … Read more
There are 5 6 NINE (or 63*, depending how you count) different ways to write multi-line strings in YAML. TL;DR Use > most of the time: interior line breaks are stripped out, although you get one at the end: key: > Your long string here. Use | if you want those linebreaks to be preserved … Read more