numpy の基本 その3

programming python numpy
  • work1():
    • numpy.ndarray のメソッド
      • a.shape: 行列のサイズ(行,列)をタプルで返す
      • a.size: 行列の全要素数を返す
  • work2():
    • 参考URLに記載されていた練習問題の解答
#!/usr/bin/env python
#coding:utf-8
import numpy as np


def work1():
    a = np.arange(12).reshape(3,4)

    print a.shape   # (3,4)
    print a.size    # 12


def work2():
    """
    練習問題 ：以下の配列を最も単純な解答で作成せよ.
 
    [[ 1.  1.  1.  1.]
     [ 1.  1.  1.  1.]
     [ 1.  1.  1.  2.]
     [ 1.  6.  1.  1.]]

    [[0 0 0 0 0]
     [2 0 0 0 0]
     [0 3 0 0 0]
     [0 0 4 0 0]
     [0 0 0 5 0]
     [0 0 0 0 6]]    
    """

    a = np.ones((4,4))
    a[2][3] = 2
    a[3][1] = 6
    
    b = np.zeros((6,5))
    b[1:6] = np.diag([2,3,4,5,6])

    print a
    print b


if __name__ == "__main__":
    work1()
    work2()