这个 Go 的 for 循环条件判断有什么问题 - V2EX
The Go Programming Language
http://golang.org/
Go Playground
Go Projects
Revel Web Framework
n0bug

这个 Go 的 for 循环条件判断有什么问题

  •  
  •   n0bug Jun 23, 2023 2524 views
    This topic created in 1055 days ago, the information mentioned may be changed or developed.

    请问这段代码为什么没有任何输出?

    按理说在 i = 2 和 4 的时候,visit [i] = true, printf 应该打印出 i 。

    然而 go run main.go 的结果没有任何输出。

    package main import ( "fmt" ) func main() { visit := []bool{false, false, true, false, true, false} for i := 0; i < len(visit) && visit[i]; i++ { fmt.Printf("%d\n", i) } } 
    11 replies    2023-06-24 16:41:47 +08:00
    northess
        1
    northess  
       Jun 23, 2023
    数组的第一个不是写的 false 吗
    ClarkAbe
        2
    ClarkAbe  
    &nbp;  Jun 23, 2023 via Android
    你先去把任意一个语言的循环关键字教程看一遍...
    Ericcccccccc
        3
    Ericcccccccc  
       Jun 23, 2023
    我估计你想要的是
    for i := 0; i < len(visit); i++ {
    if visit[i]
    fmt.Printf("%d\n", i)
    }
    nirvam
        4
    nirvam  
       Jun 23, 2023
    看 for 那行,想想 visit[i]是 false 的时候,会发生什么?
    dobelee
        5
    dobelee  
       Jun 23, 2023
    很容易找到问题,for 的条件打印出来是 false ,根本没进去。
    fmt.Println(0 < len(visit) && visit[0]) // false

    正确的写法:
    ```
    for i, val := range visit {
    if val {
    fmt.Println(i, val)
    }
    }
    ```
    n0bug
        6
    n0bug  
    OP
       Jun 23, 2023
    哦。。。 是我疏忽了。。
    感谢各位,结贴了。
    MFWT
        7
    MFWT  
       Jun 23, 2023
    展开条件

    你猜猜

    i < 6 && visit[0]

    的值是什么?
    realpg
        8
    realpg  
    PRO
       Jun 23, 2023
    技术不到家,非得整花活,俗称人菜瘾大,而且写这种代码被优化概率很高

    ↓这么写,是个人就能看明白
    @Ericcccccccc #3
    hzzhzzdogee
        9
    hzzhzzdogee  
       Jun 23, 2023
    be nice, guys
    mengdodo
        10
    mengdodo  
       Jun 24, 2023
    for 循环体内接 if 判断不好吗,非得一行解决所有?
    Crazypointer
        11
    Crazypointer  
       Jun 24, 2023
    代码压行压出 bug 了
    About     Help     Advertise     Blog     API     FAQ     Solana     1035 Online   Highest 6679       Select Language
    创意工作者们的社区
    World is powered by solitude
    VERSION: 3.9.8.5 51ms UTC 22:36 PVG 06:36 LAX 15:36 JFK 18:36
    Do have faith in what you're doing.
    ubao msn snddm index pchome yahoo rakuten mypaper meadowduck bidyahoo youbao zxmzxm asda bnvcg cvbfg dfscv mmhjk xxddc yybgb zznbn ccubao uaitu acv GXCV ET GDG YH FG BCVB FJFH CBRE CBC GDG ET54 WRWR RWER WREW WRWER RWER SDG EW SF DSFSF fbbs ubao fhd dfg ewr dg df ewwr ewwr et ruyut utut dfg fgd gdfgt etg dfgt dfgd ert4 gd fgg wr 235 wer3 we vsdf sdf gdf ert xcv sdf rwer hfd dfg cvb rwf afb dfh jgh bmn lgh rty gfds cxv xcv xcs vdas fdf fgd cv sdf tert sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf sdf shasha9178 shasha9178 shasha9178 shasha9178 shasha9178 liflif2 liflif2 liflif2 liflif2 liflif2 liblib3 liblib3 liblib3 liblib3 liblib3 zhazha444 zhazha444 zhazha444 zhazha444 zhazha444 dende5 dende denden denden2 denden21 fenfen9 fenf619 fen619 fenfe9 fe619 sdf sdf sdf sdf sdf zhazh90 zhazh0 zhaa50 zha90 zh590 zho zhoz zhozh zhozho zhozho2 lislis lls95 lili95 lils5 liss9 sdf0ty987 sdft876 sdft9876 sdf09876 sd0t9876 sdf0ty98 sdf0976 sdf0ty986 sdf0ty96 sdf0t76 sdf0876 df0ty98 sf0t876 sd0ty76 sdy76 sdf76 sdf0t76 sdf0ty9 sdf0ty98 sdf0ty987 sdf0ty98 sdf6676 sdf876 sd876 sd876 sdf6 sdf6 sdf9876 sdf0t sdf06 sdf0ty9776 sdf0ty9776 sdf0ty76 sdf8876 sdf0t sd6 sdf06 s688876 sd688 sdf86