comma

问题 int m = 5, d = 12, y = 1975, val; // May 12, 1975 Can someone please explain the function/purpose of the comma operator in the line of code below: val = (d+=m<3?y--:y-2,23*m/9+d+4+y/4-y/100+y/400)%7; The above line was written by Mike Keith to calculate the day of the week given the date (d = day, m = month, y = year). Where Sunday = 0, Monday = 1, Tuesday = 2, Wednesday = 3, Thursday = 4, Friday = 5, Saturday = 6. I understand that the y-- gets executed if d+=m<3 is true, else the y-2 is

问题 Haskell blew my mind yet again when I realised that (x,y) Is just syntactic sugar for (,) x y Naturally I wanted to extend this to larger tuples. But (,) x ((,) y z) Gave me (x,(y,z)) Which was not what I was looking for. On a whim, I tried (,,) x y z And it worked, giving exactly what I wanted: (x,y,z) This raised the question: How far can you take it? Much to my astonishment, there seemed to be no limit. All of the below are valid operators: (,) (,,) (,,,) (,,,,) --etc (,,,,,,,,,,,,,,) (,,,

问题 R users I have a data frame similar to this: a <- c("John, 3 years") b <- c("Mokobe, 11 years") c <- c("Ivan") df <- rbind(a,b,c) df [,1] a "John, 3 years" b "Mokobe, 11 years" c "Ivan" Which function should I use to split the column after comma to get: df [,1] [,2] John 3 years Mokobe 11 years Ivan NA 回答1: we can do a strsplit by the delimiter , and then rbind the list elements after padding with NA at the end to make length same for each list element lst <- strsplit(df[,1], ", ") do.call

问题 How can I split string (from a textbox) by commas excluding those in double quotation marks ( without getting rid of the quotation marks ), along with other possible punctuation marks (e.g. ' . ' ' ; ' ' - ')? E.g. If someone entered the following into the textbox: apple, orange, "baboons, cows", rainbow, "unicorns, gummy bears" How can I split the above string into the following (say, into a List)? apple orange "baboons, cows" rainbow "Unicorns, gummy bears..." Thank you for your help! 回答1:

问题 I have read that comma operator is used to assign expression, and the right expression is supplied to lvalue. But why does this program assign left expression to lvalue when not using parenthesis.I am using turbo c compiler int b=2; int a; a=(b+2,b*5); // prints 10 as expected a=b+2,b*5; // prints 4 when not using parenthesis Also the following works int a =(b+2,b*5); And this generates error,I couldn't understand the reason. int a =b+2,b*5; // Error 回答1: Because precedence of , operator is

问题 How to build a regex to remove all commas that are inside quotes(") using C# and then substitute them by @? Example : Initial string like this = (value 1,value 2,"value3,value4,value5",value 6) Expected string like this = (value 1,value 2,"value3@value4@value5", value 6) 回答1: You can use string input = "(value 1,value 2,\"value3,value4,value5\",value 6)"; var regex = new Regex("\\\"(.*?)\\\""); var output = regex.Replace(input, m => m.Value.Replace(',','@')); 回答2: string input = "= (value 1

问题 I want to change on the yticklabel decimal separator from a decimal point to a comma, but leave the format of the offset text (1e-14), after using code from this code or that code. My questions: How can I change the point to a comma and save 1e-14? How can I change e to E in the offset text? I am using Python 3.5 回答1: To change the decimal separator from a point to a comma, you can change the locale to somewhere where a comma is used. For example, here I set it to German: #Locale settings

问题 I was looking at "How to properly use references with variadic templates," and wondered how far comma expansion can go. Here's a variant of the answer: inline void inc() { } template<typename T,typename ...Args> inline void inc(T& t, Args& ...args) { ++t; inc(args...); } Since variadic arguments are expanded to a comma -separated list of their elements, are those commas semantically equivalent to template/function-argument separators, or are they inserted lexically , making them suitable for

问题 I have several checkboxes with a name array and I want the output of the checked boxes to be a variable with a comma separated list. <input type="checkbox" name="example[]" value="288" /> <input type="checkbox" name="example[]" value="289" /> <input type="checkbox" name="example[]" value="290" /> For example if the first and last box are selected the output will be: var output = "288,290"; How can I do this with jQuery? 回答1: You can use :checkbox and name attribute selector ( :checkbox[name

问题 Given the following bar chart: import numpy as np import matplotlib.pyplot as plt import pandas as pd df = pd.DataFrame({'A': ['A', 'B'], 'B': [1000,2000]}) fig, ax = plt.subplots(1, 1, figsize=(2, 2)) df.plot(kind='bar', x='A', y='B', align='center', width=.5, edgecolor='none', color='grey', ax=ax) plt.xticks(rotation=25) plt.show() I'd like to display the y-tick labels as thousands of dollars like this: $2,000 I know I can use this to add a dollar sign: import matplotlib.ticker as mtick fmt