# Python complex() Function

Converts a string or number to a complex number

## Usage

The `complex()`

function creates a complex number when real and imaginary parts are specified.

It can also convert a string to a complex number.

The complex number is returned in the form of real + imaginary, where the imaginary part is followed by a j.

## Syntax

complex(real,imaginary)

Parameter | Condition | Description |

real | Optional | The real part of the complex number. Default is 0. |

imaginary | Optional | The imaginary part of the complex number. Default is 0. |

## Creating Complex Numbers

You can create a complex number by specifying real and imaginary parts.

```
x = complex(3, 2)
print(x)
# Prints (3+2j)
x = complex(-3, 2)
print(x)
# Prints (-3+2j)
x = complex(3, -2)
print(x)
# Prints (3-2j)
```

If you omit one of the arguments, it is assumed as 0; because the default value of real and imaginary parameters is 0.

```
# omit imaginary part
x = complex(3)
print(x)
# Prints (3+0j)
# omit real part
x = complex(0, 4)
print(x)
# Prints 4j
# omit both
x = complex()
print(x)
# Prints 0j
```

## Convert a String to a Complex Number

You can convert a string to a complex number by specifying the first parameter as a string like `'3+4j'`

. In this case the second parameter should be omitted.

```
# Convert a string '3+4j' to a complex number
x = complex('3+4j')
print(x)
# Prints (3+4j)
```

When converting from a string, the string must not contain whitespace around the central + or – operator. Otherwise, the function raises `ValueError`

.

```
# Triggers ValueError: complex() arg is a malformed string
x = complex('3 + 4j')
print(x)
```

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