Create Python-Function-Complex.md

Python-Function-Complex.md

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+# Python Complex()
+
+`complex()` is a built-in function in Python 3 that hanldles the creation of a [complex number](https://www.mathsisfun.com/numbers/complex-numbers.html) according to the arguments passed. It returns a complex number with the value `real + imag*1j` when called in form of `complex(real, imag)` or converts a string or number to a complex number.
+
+## Arguments and Return Values
+
+This function takes two types of arguments which are discussed below :
+
+#### Numeric Arguments
+
+When called with two arguments, both being numbers of any numeric type (including complex), this function returns a complex number using both arguments.
+`complex(x, y)` function returns a complex number with the value `x + y*1j`
+
+```python
+>>> complex(3, 2)
+(3+2j)
+>>> complex(3+4j, 6)
+(3+10j)
+```
+When called with one numeric argument, it returns a complex number using  the argument as the real part and an imaginary part of zero.
+
+```python
+>>> complex(4)
+(4+0j)
+```
+If called with no arguments, it returns a complex zero.
+
+```python
+>>> complex()
+0j
+```
+#### String Argument
+
+If the first argument is a string, it will be interpreted as a *complex number* and the function must be called without a second parameter. It will return the interpreted  complex number.
+
+```python
+>>> complex('3+4j')
+(3+4j)
+```
+The string must be in the form of a valid complex number, otherwise the function will raise a `ValueError` exception and it must not contain whitespace around the central + or - operator. For example, `complex('1+2j')` is fine, but `complex('1 + 2j')` raises `ValueError`.
+
+## Examples
+
+```python
+print(complex(4, 5))      # prints (4+5j)
+print(complex(6))         # prints (6+0j)
+print(complex())          # prints 0j
+print(complex(2.5,5))     # prints (2.5+5j)
+print(complex(5,6+8j))    # prints (-3+6j) as 5+(6+8j)*1j = -3+6j
+print(complex('10+20j'))  # prints (10+20j)
+```
+:rocket: [Run Code](https://repl.it/CTGi/3)
+
+[Official Documentation](https://docs.python.org/3/library/functions.html#complex)