Create Python-Function-Complex.md

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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 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
+Two types of arguments can be passed.
+
+1. **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
+    ```
+
+2. **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.
+
+      - The string 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)