引导4，每行可变列数

如果你想每行最多有5列，这样每一行的列数仍然只占一行的1/5，解决方案是使用Bootstrap 4的mixins:

SCSS:

.col-2-4 {
    @include make-col-ready(); // apply standard column margins, padding, etc.
    @include make-col(2.4); // 12/5 = 2.4
}
.col-sm-2-4 {
    @include make-col-ready();
    @include media-breakpoint-up(sm) {
        @include make-col(2.4);
    }
}
.col-md-2-4 {
    @include make-col-ready();
    @include media-breakpoint-up(md) {
        @include make-col(2.4);
    }
}
.col-lg-2-4 {
    @include make-col-ready();
    @include media-breakpoint-up(lg) {
        @include make-col(2.4);
    }
}
.col-xl-2-4 {
    @include make-col-ready();
    @include media-breakpoint-up(xl) {
        @include make-col(2.4);
    }
}

HTML:

<div class="container">    
  <div class="row">
    <div class="col-12 col-sm-2-4">1 of 5</div>
    <div class="col-12 col-sm-2-4">2 of 5</div>
    <div class="col-12 col-sm-2-4">3 of 5</div>
    <div class="col-12 col-sm-2-4">4 of 5</div>
    <div class="col-12 col-sm-2-4">5 of 5</div>
  </div>
  <div class="row">
    <div class="col-12 col-sm-2-4">1 of 2</div> <!-- same width as column "1 of 5" above -->
    <div class="col-12 col-sm-2-4">2 of 2</div> <!-- same width as column "2 of 5" above -->
  </div>
</div>

如果使用bootstrap 4和SASS (+ bootstrap变量)，您可以使用以下简化的答案:

@each $breakpoint in map-keys($grid-breakpoints) {
  $infix: breakpoint-infix($breakpoint, $grid-breakpoints);

  .col#{$infix}-fifth {
    @extend %grid-column;
  }

  @include media-breakpoint-up($breakpoint, $grid-breakpoints) {
    .col#{$infix}-fifth {
      flex: 0 0 20%;
      max-width: 20%;
    }
  }
}

还支持断点，您可以简单地添加新的.col#{$infix}-xxx类

我对这个问题的首选方法是基于make-grid-columns mixin，利用现有的Bootstrap变量创建一个SASS mixin。

// Custom Grid Columns
// 
// $name - determines the class names: eg. ".col-5ths, .col-sm-5ths ..."
// $size - determines the width (2.4 is one fifth of 12, the default number of columns)
@mixin custom-grid-columns($name, $size, $grid-columns: $grid-columns, $breakpoints: $grid-breakpoints) {
    $columns: round($grid-columns / $size);

    %custom-grid-column {
        @include make-col-ready();
    }

    @each $breakpoint in map-keys($breakpoints) {
        $infix: breakpoint-infix($breakpoint, $breakpoints);

        .col#{$infix}-#{$name} {
            @extend %custom-grid-column;
        }

        @include media-breakpoint-up($breakpoint, $breakpoints) {
            // Create column
            .col#{$infix}-#{$name} {
                @include make-col($size);
            }

            // Create offset
            @if not ($infix=="") {
                .offset#{$infix}-#{$name} {
                    @include make-col-offset($size);
                }
            }
        }
    }
}

然后可以调用mixin来生成自定义列类和偏移量类。

@include custom-grid-columns('5ths', 2.4);

这个很棒:http://www.ianmccullough.net/5-column-bootstrap-layout/

只做:

<div class="col-xs-2 col-xs-15">

和CSS:

.col-xs-15{
    width:20%;
}

一个解决方案，不需要大量的CSS，也不调整bootstrap默认12col布局:

http://jsfiddle.net/0ufdyeur/1/

HTML:

<div class="stretch">
  <div class="col-lg-2"></div>
  <div class="col-lg-2"></div>
  <div class="col-lg-2"></div>
  <div class="col-lg-2"></div>
  <div class="col-lg-2"></div>
</div>

CSS:

@media (min-width: 1200px) { /*if not lg, change this criteria*/
  .stretch{
    width: 120%; /*the actual trick*/
  }
}

用于引导4.4+

使用全新的row-cols-n类。

添加row-cols-5类到你的.row div。不需要自定义CSS。 参见4.4文档中的row-cols: https://getbootstrap.com/docs/4.4/layout/grid/#row-columns

对于引导4.4之前的引导4版本

Copy CSS below (awesome CSS by Bootstrap authors) and add it to your project Read the docs cited above to use it correctly. .row-cols-1>*{-ms-flex:0 0 100%;flex:0 0 100%;max-width:100%}.row-cols-2>*{-ms-flex:0 0 50%;flex:0 0 50%;max-width:50%}.row-cols-3>*{-ms-flex:0 0 33.333333%;flex:0 0 33.333333%;max-width:33.333333%}.row-cols-4>*{-ms-flex:0 0 25%;flex:0 0 25%;max-width:25%}.row-cols-5>*{-ms-flex:0 0 20%;flex:0 0 20%;max-width:20%}.row-cols-6>*{-ms-flex:0 0 16.666667%;flex:0 0 16.666667%;max-width:16.666667%}@media (min-width:576px){.row-cols-sm-1>*{-ms-flex:0 0 100%;flex:0 0 100%;max-width:100%}.row-cols-sm-2>*{-ms-flex:0 0 50%;flex:0 0 50%;max-width:50%}.row-cols-sm-3>*{-ms-flex:0 0 33.333333%;flex:0 0 33.333333%;max-width:33.333333%}.row-cols-sm-4>*{-ms-flex:0 0 25%;flex:0 0 25%;max-width:25%}.row-cols-sm-5>*{-ms-flex:0 0 20%;flex:0 0 20%;max-width:20%}.row-cols-sm-6>*{-ms-flex:0 0 16.666667%;flex:0 0 16.666667%;max-width:16.666667%}}@media (min-width:768px){.row-cols-md-1>*{-ms-flex:0 0 100%;flex:0 0 100%;max-width:100%}.row-cols-md-2>*{-ms-flex:0 0 50%;flex:0 0 50%;max-width:50%}.row-cols-md-3>*{-ms-flex:0 0 33.333333%;flex:0 0 33.333333%;max-width:33.333333%}.row-cols-md-4>*{-ms-flex:0 0 25%;flex:0 0 25%;max-width:25%}.row-cols-md-5>*{-ms-flex:0 0 20%;flex:0 0 20%;max-width:20%}.row-cols-md-6>*{-ms-flex:0 0 16.666667%;flex:0 0 16.666667%;max-width:16.666667%}}@media (min-width:992px){.row-cols-lg-1>*{-ms-flex:0 0 100%;flex:0 0 100%;max-width:100%}.row-cols-lg-2>*{-ms-flex:0 0 50%;flex:0 0 50%;max-width:50%}.row-cols-lg-3>*{-ms-flex:0 0 33.333333%;flex:0 0 33.333333%;max-width:33.333333%}.row-cols-lg-4>*{-ms-flex:0 0 25%;flex:0 0 25%;max-width:25%}.row-cols-lg-5>*{-ms-flex:0 0 20%;flex:0 0 20%;max-width:20%}.row-cols-lg-6>*{-ms-flex:0 0 16.666667%;flex:0 0 16.666667%;max-width:16.666667%}}@media (min-width:1200px){.row-cols-xl-1>*{-ms-flex:0 0 100%;flex:0 0 100%;max-width:100%}.row-cols-xl-2>*{-ms-flex:0 0 50%;flex:0 0 50%;max-width:50%}.row-cols-xl-3>*{-ms-flex:0 0 33.333333%;flex:0 0 33.333333%;max-width:33.333333%}.row-cols-xl-4>*{-ms-flex:0 0 25%;flex:0 0 25%;max-width:25%}.row-cols-xl-5>*{-ms-flex:0 0 20%;flex:0 0 20%;max-width:20%}.row-cols-xl-6>*{-ms-flex:0 0 16.666667%;flex:0 0 16.666667%;max-width:16.666667%}}