subtraction

I want to subtract y from x, which means remove one "A", three "B" and one "E" from x, so xNew will be c("A", "C", "A","B","D") . It also means length(xNew)=length(x) - length(y) x <- c("A","A","C","A","B","B","B","B","D","E") y <- c("A","B","B","B","E") setdiff doesn't work because xNew <- setdiff(x,y) xNew [1] "C" "D" match also doesn't work xNew <- x[-match(y,x)] xNew [1] "A" "C" "A" "B" "B" "B" "D" It removes "B" on the fifth position 3 times, so there are still three "B" left. Is anyone know how to do this, is there a function available in R or we should write a private function? Thanks a

I am looking for the quickest method to subtract all elements of array A, from all elements of array B. The only way I know how to do it is: a = np.array([1,2,3]) b = np.array([1,2,3]) new = [] for i in a: new.append(b - a[i]) Ideally, I would like to end up with a matrix new which would be qual to [0,1,2;-1,0,1;-2,-1,0] I would also like to extend this type of operation to Pandas timedelta series. For example, I can do this: a=np.array([1,2,3]) b=np.array([1,2,3]) aT = pd.to_timedelta(a,'D') bT = pd.to_timedelta(b,'D') new = [] for i in aT: x.append(bT - i) and end up with this:

This question already has an answer here: Java - Subtract Days from date [duplicate] 6 answers I am trying to do something really simple. I am trying to subtract 2 days from the current day. I get the number of hours from the UI. So in this example, I get 48 hours from the UI. I am doing the following and I don't know what i'm doing wrong here. I think the result of this is it only subtracts a few minutes from the time. long timeInEpoch = (currentMillis()/1000 - (48 * 60 * 60)); //48 comes from UI public long currentMillis(){ return new Date().getTime(); } d = new Date(timeInEpoch * 1000); I

all I am trying to implement a floating point arithmetic library and I have trouble understanding the algorithm of subtracting floats. I have implemented addition succesfully and I thought that subtraction was just a special case of it but it seems I am making a mistake somewhere. I am adding the code here just for reference, it has many self explanatory functions but I don't expect someone to understand it 100%. What I would like help with is the algorithm. We follow the same method as with adding float numbers except, when we add the mantissas, we convert the negative one(the one we subtract

df1: City, 2015-12-31, 2016-01-31, ... YYZ 562.14, -701.18, ... DFW 562.14, -701.18, ... YYC 562.14, -701.18, ... df2: City, 2015-12-31, 2016-01-31, ... SFO 562.14, -701.18, ... PDX 562.14, -701.18, ... LAX 562.14, -701.18, ... I want to subtract df1 from df2. i.e. subtract values in respective date columns. I tried the following: df2.subtract(df1, fill_value=0) But I receive the following error: TypeError: unsupported operand type(s) for -: 'str' and 'float' I think the error is because the operation cannot understand how to subtract strings in the City column, which obviously makes sense

I am trying to create a calculator, but I am having trouble writing a function that will subtract numbers from a list. For example: class Calculator(object): def __init__(self, args): self.args = args def subtract_numbers(self, *args): return ***here is where I need the subtraction function to be**** For addition, I can simply use return sum(args) to calculate the total but I am unsure of what I can do for subtractions. georg from functools import reduce # omit on Python 2 import operator a = [1,2,3,4] xsum = reduce(operator.__add__, a) # or operator.add xdif = reduce(operator.__sub__, a) # or