I'm just learning R, so please forgive what I'm sure is a very elementary question. How do I take the real part of a complex number?
Definition of real part : the term in a complex number (such as 2 in 2 + 3i) that does not contain the imaginary unit as a factor.
From the second definition, we can conclude that any real number is also a complex number. In addition, there can be complex numbers that are neither real nor imaginary, like 4 + 2 i 4+2i 4+2i4, plus, 2, i.
A complex number is a number that can be written in the form a + b i a + bi a+bi, where a and b are real numbers and i is the imaginary unit defined by i 2 = − 1 i^2 = -1 i2=−1. The set of complex numbers, denoted by C, includes the set of real numbers (R) and the set of pure imaginary numbers.
Complex numbers are the numbers that are expressed in the form of a+ib where, a,b are real numbers and 'i' is an imaginary number called “iota”. The value of i = (√-1). For example, 2+3i is a complex number, where 2 is a real number (Re) and 3i is an imaginary number (Im).
If you read the help file for complex
(?complex
), you will see a number of functions for performing complex arithmetic. The details clearly state
The functions
Re
,Im
,Mod
,Arg
andConj
have their usual interpretation as returning the real part, imaginary part, modulus, argument and complex conjugate for complex values.
Therefore
Use Re
:
Re(1+2i)
# 1
For the imaginary part:
Im(1+2i)
# 2
?complex
will list other useful functions.
Re(z)
and
Im(z)
would be the functions you're looking for.
See also http://www.johnmyleswhite.com/notebook/2009/12/18/using-complex-numbers-in-r/
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