TypeError with map with no len()

[john polo]

On 9/25/2017 5:37 PM, Thomas Jollans wrote:
> On 25/09/17 18:44, john polo wrote:
>> Python List,
>>
>> I am trying to make practice data for plotting purposes. I am using
>> Python 3.6. The instructions I have are
>>
>> import matplotlib.pyplot as plt
>> import math
>> import numpy as np
>> t = np.arange(0, 2.5, 0.1)
>> y1 = map(math.sin, math.pi*t)
> If you use np.sin instead of math.sin, you don't have to use map: Most
> numpy functions operate elementwise on arrays (for example, you're
> multiplying math.pi with an array - something that wouldn't work with a
> list).
>
> Here's the numpy way of doing this:
>
> t = np.arange(0, 2.5, 0.1)
> y1 = np.sin(np.pi * t)
>
> Without using numpy at all, this might be
>
> t = [i * 0.1 for i in range(25)]
> y1 = [math.pi * a for a in t]
The numpy way looks like a great alternative. Thank you, Thomas.

John