Np Array values are being changed without doing stuff

Question

Why does :

print(np.delete(MatrixAnalytics(Cmp),[0],1))
MyNewMatrix = np.delete(MatrixAnalytics(Cmp),[0],1)
print("SecondPrint")
print(MyNewMatrix)

returns :

[[ 2.  2.  2.  2.  2.]
 [ 1.  2.  2.  2.  2.]
 [ 1.  2.  0.  2.  2.]
 [ 2.  2.  2.  2.  2.]
 [ 2.  2.  2.  0.  0.]
 [ 1.  2.  2.  0.  2.]
 [ 1.  2.  2.  2.  2.]
 [ 1.  2.  2.  2. nan]
 [ 2.  2.  2.  2.  2.]
 [ 2.  2.  2.  2. nan]]
Second Print
[[-1.  0.  0.  0.  0.]
 [-1.  0.  0.  0.  0.]
 [-1.  0. -1.  0.  0.]
 [-1.  0.  0.  0.  0.]
 [-1.  0.  0. -1.  0.]
 [-1.  0.  0. -1.  0.]
 [-1.  0.  0.  0.  0.]
 [-1.  0.  0.  0. nan]
 [-1.  0.  0.  0.  0.]
 [-1.  0.  0.  0. nan]]

This is weird, and can't figure this out. Why Would the values change without any line of code between 3 print ?

def MatrixAnalytics(DataMatrix):
    AnalyzedMatrix = DataMatrix
    for i in range(len(AnalyzedMatrix)): #Browse Each Column
        for j in range(len(AnalyzedMatrix[i])): #Browse Each Line
            if j>0:
                if AnalyzedMatrix[i][j] > 50:
                    if AnalyzedMatrix[i][j] > AnalyzedMatrix[i][j-1]:
                        AnalyzedMatrix[i][j] = 2
                    else:
                        AnalyzedMatrix[i][j] = 1
                else:
                    if AnalyzedMatrix[i][j] <50:
                        if AnalyzedMatrix[i][j] > AnalyzedMatrix[i][j-1]:
                            AnalyzedMatrix[i][j] = 0
                        else:
                            AnalyzedMatrix[i][j] = -1                          
    return AnalyzedMatrix

The input array is :

[[55.  57.6 57.2 57.  51.1 55.9]
 [55.3 54.7 56.1 55.8 52.7 55.5]
 [55.5 52.  52.2 49.9 53.8 55.6]
 [54.9 57.8 57.6 53.6 54.2 59.9]
 [47.9 50.7 53.3 52.5 49.9 45.8]
 [57.  56.2 58.3 55.4 47.9 56.5]
 [56.6 54.2 57.6 54.7 50.1 53.6]
 [54.7 53.4 52.  52.  50.9  nan]
 [51.4 51.5 51.2 53.  50.1 50.1]
 [55.3 58.7 59.2 56.4 53.   nan]]

It seems that it call again the function MatrixAnalytics But I don't understand why

**

Doing this works :

**

MyNewMatrix = np.delete(MatrixAnalytics(Cmp),[0],1)
print(MyNewMatrix)
MyNewMatrix = np.delete(MatrixAnalytics(Cmp),[0],1)
print("SecondPrint")
print(MyNewMatrix)

Answer 1

I believe you want same output in both the cases, Sadly the thing is np.delete performs changes in the array itself, so when you called the first line (np.delete(MatrixAnalytics(Cmp),[0],1)) it deletes the 0th column and saves it in matrixanalytics, so never call this function in print statement, either call it during assignment or even without assignment as it will make the changes in the given array itself, but never in print since the column would be lost in the print statement.