大约有 47,000 项符合查询结果（耗时：0.0457秒） [XML]
Count the number occurrences of a character in a string
...'s the simplest way to count the number of occurrences of a character in a string?
19 Answers
...
How do I update all my CPAN modules to their latest versions?
...
why using such extra tools while there's a built-in solution (see second answer)?
– eav
Nov 8 '12 at 8:37
4
...
Scala 2.8 breakOut
... breakOut? Consider the example given for the question, You take a list of strings, transform each string into a tuple (Int, String), and then produce a Map out of it. The most obvious way to do that would produce an intermediary List[(Int, String)] collection, and then convert it.
Given that map u...
Best GWT widget library? [closed]
...se due to the dependency on some external AJAX library. This, as well, add extra size to your solution. Note, as well, that most of the widget libraries depend on one or more additional external components.
– IgorM
May 18 '09 at 20:09
...
Evaluating a mathematical expression in a string
...s a class, so I can use it
more easily in other places.
'''
class NumericStringParser(object):
'''
Most of this code comes from the fourFn.py pyparsing example
'''
def pushFirst(self, strg, loc, toks):
self.exprStack.append(toks[0])
def pushUMinus(self, strg, loc, to...
Asking the user for input until they give a valid response
... = input("Please enter your age: ")
try:
# try and convert the string input to a number
age = int(input_value)
except ValueError:
# tell the user off
print("{input} is not a number, please enter a number only".format(input=input_value))
if age >= 18:
pr...
Managing constructors with many parameters in Java
... Consider the following example
public class StudentBuilder
{
private String _name;
private int _age = 14; // this has a default
private String _motto = ""; // most students don't have one
public StudentBuilder() { }
public Student buildStudent()
{
return new ...
Red black tree over avl tree
...ack tree.
AVL trees store the balance factor at each node. This takes O(N) extra space. However, if we know that the keys that will be inserted in the tree will always be greater than zero, we can use the sign bit of the keys to store the colour information of a red-black tree. Thus, in such cases r...
How to do ToString for a possibly null object?
...# 6.0 we can now have a succinct, cast-free version of the orignal method:
string s = myObj?.ToString() ?? "";
Or even using interpolation:
string s = $"{myObj}";
Original Answer:
string s = (myObj ?? String.Empty).ToString();
or
string s = (myObjc ?? "").ToString()
to be even more concise.
Unfo...
Django REST Framework: adding additional field to ModelSerializer
...
So, based on this answer, if you want to pass say 12 extra fields to your serializer, you need to define 12 specific methods for each field that just returns foo.field_custom ?
– AlxVallejo
Apr 13 '18 at 19:13
...