Variable overwrite, Not comprehensible

Getting Help
1

I do not know how to describe it. :confused:

 if aa[0].Name != "" {

				a.Direktekosten = aa
				e = clJahrep(e, a.Direktekosten[0].Summe) //step 1
			}

			//call

			a.Rohgewinn = append(a.Rohgewinn, GXAnsichtenSumme{Summe: e, Name: "Rohgewinn"}) //step 2

		log.Println(a.Rohgewinn) //step 3

			aa = getXAnsichtInhalt(r, b.Plan_key, "personalkosten")

			if aa[0].Name != "" {

				a.Personalaufwand = aa
				e = clJahrem(e, a.Direktekosten[0].Summe) //Step 4
			}
			log.Println(a.Rohgewinn) //step 5

Step 1:

i write a struct in e

Step 2:

i set e in a.Rohgewinn

Step 3:

look in a.Rohgewinn and the result is right

Step 4:

Continue to calculate object e

Step 5:

a,Rohgewinn result is change?

Why???

2

Can you make a reproducible program on play.golang.org?

4

Step one in troubleshooting somelike this is to reduce the program to the minimum that still exhibits the problem. It is then usually quite straightforward to locate.

5

The problem is:

Object e becomes in object a.Rohgewinn. If “e” is later calculated, the value in “a.Rohgewinn” is also changed.

7

https://play.golang.org/p/NgbJ_J2htE

8

What output are you expecting?

9

I want the “a.Rohgewinn” not changed if I “e” further change. https://play.golang.org/

10

It’s not.

a.Rohgewinn = append(a.Rohgewinn, GXAnsichtenSumme{Summe: e, Name: "Rohgewinn"})

places e, a slice, into a.Rohgewinn. Here, e is copied, but the array backing e is not.

Slices are essentially a struct that stores the slice’s length, capacity, and a pointer to an array.

The code you provided copied the struct, but not the array.

1 Like
11

Okay i understand …

I solved

e2 = make([]GXSumme, len(e))
copy(e2, e)
a.Betriebsergebnis = append(a.Betriebsergebnis, GXAnsichtenSumme{Summe: e2, Name: "Betriebsergebnis"})
e2 = nil

thx

1 Like
12

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