Matrix flip horizontal or vertical

Question

I am trying to write a python function to flip a matrix horizontal or vertical. To write a Python function matrixflip(m,d) that takes a two-dimensional matrix and a direction, where d is either 'h' or 'v'. If d == 'h' , the function should return the matrix flipped horizontally. If d == 'v' , the function should return the matrix flipped vertically. For any other values of d, the function should return m unchanged. In all cases, the argument m should remain undisturbed by the function.

import numpy as np
def matrixflip(m,d):
    m = myl
    myl = np.array([[1, 2], [3, 4]])
    if d=='v': 
        return np.flip(contour, axis=0)
    elif d=='h':
        return np.flip(contour, axis=1)

I expect the output as

>>> myl = [[1,2],[3,4]]

>>> myl
[[1, 2], [3, 4]]  

>>> matrixflip(myl,'h')
[[2, 1], [4, 3]]

>>> myl
[[1, 2], [3, 4]]  

>>> matrixflip(myl,'v')
[[3, 4], [1, 2]]  

>>> myl
[[1, 2], [3, 4]]  

Answer 1

I have found what may be the issue, when you assign a list to another list m = myl you are not creating a new copy of that list to play around with, so any changes to m will affect myl. By replacing that with tempm = m.copy() you get a new version of the list that can be bent to your will. The following should work nicely:

def matrixflip(m,d):
    tempm = m.copy()
    if d=='h':
        for i in range(0,len(tempm),1):
                tempm[i].reverse()
    elif d=='v':
        tempm.reverse()
    return(tempm)

Answer 2

Try this:

import numpy as np
def matrixflip(m,d):
    myl = np.array(m)
    if d=='v': 
        return np.flip(myl, axis=0)
    elif d=='h':
        return np.flip(myl, axis=1)

Answer 3

def matrixflip(m,d):
    if d=='h':
        m=myl
        for i in range(0,len(m),1):
                    m[i].reverse()
        return(m)
    elif d=='v':
        m=myl
        m.reverse()
        return(m)
    else:
       return(m)

Answer 4

Try this one

def matrixflip(a,b):
    temp=[]
    for i in range(len(a)):
        temp=temp+[a[i][:]]
    if b=='h':
        for i in range(len(temp)):
            temp[i].reverse()
            return(temp)

    elif b=='v':
        temp.reverse()
        return(temp)

Answer 5

def matrixflip(a,b):
    temp=[]
    for i in range(len(a)):
        temp=temp+[a[i][:]]
    if b=='h':
        for i in range(len(temp)):
            temp[i].reverse()
            i=i+1
        return temp
    elif b=='v':
      temp.reverse()
      return(temp)   

Answer 6

def matrixflip(a,b):
    temp=[]

    for i in range(len(a)):
        temp=temp+[a[i][:]]

    if b=='h':
      for i in range(0,len(temp),1):
              temp[i].reverse()
    elif b=='v':
        temp.reverse()
    return(temp)

Answer 7

Interesting question. You can use the numpy function flip.

import numpy as np
myl = [[1,2],[3,4]]

For horizontal flip use index 0:

myl_flip_h = np.flip(myl,0) # horizontal flip

>> array([[2, 1],
   [4, 3]])

For vertical flip use index 1:

myl_flip_v = np.flip(myl,1) # vertical flip

>>array([[3, 4],
   [1, 2]])