以下是我用于打开iOS应用程序的网页上托管的元标记：
-- the "index" type
data Currency = Usd | Eur | Gbp
-- the "singleton" type
-- If you want to autogenerate this, check out the singletons
-- package on Hackage
data SCurrency (a :: Currency) where
SUsd :: Scurrency Usd
SEur :: Scurrency Eur
SGbp :: Scurrency Gbp
-- the "indexed" type
data CurrencyQty (a :: Currency) where
CurrencyQty :: SCurrency a -> Double -> CurrencyQty a
instance Num (CurrencyQty a) where
... -- you have to manually write this, I guess?
inUsd :: CurrencyQty a -> IO (CurrencyQty Usd)
inUsd (CurrencyQty SUsd x) = return x
inUsd (CurrencyQty SEur x) = fmap (*x) $ currentExchangeRate Usd Eur
inUsd (CurrencyQty SGbp x) = fmap (*x) $ currentExchangeRate Usd Gbp
只要在这些应用程序链接标记存在时单击链接，用户就会被带到网页，并且该应用程序永远不会打开。
当我删除numcols=3 # specify the number of columns you want
all_categories=df['Category_Column'].unique() # array of strings to use as your filters and titles
rows=alt.vconcat(data=df)
numrows=int(np.ceil(len(all_categories) / numcols))
pointer=0
for _ in range(numrows):
row=all_categories[pointer:pointer+numcols]
cols=alt.hconcat()
for a_chart in row:
# add your layers here
# line chart
line=alt.Chart().mark_line(point=True).encode(
x='variable',
y='value'
).transform_filter(datum.Category_Column == a_chart).properties(
title=a_chart, height=200, width=200)
# text labels
text=alt.Chart().mark_text().encode(
x='variable',
y='value'
).transform_filter(datum.Category_Column == a_chart)
both = line + text
cols |= both
rows &= cols
pointer += numcols
rows
标记时，它神奇地起作用。每次我更新元标记以确保Facebook抓取正确的标记时，我都会重新发布该链接。
Facebook是否禁用包含 <meta property="al:ios:url" content="test-scheme://open">
<meta property="al:ios:app_store_id" content="111111111">
<meta property="al:ios:app_name" content="My App">
<meta property="og:title" content="My Title">
<meta property="og:description" content="My description">
<meta property="fb:app_id" content="{my app id}">
<meta property="og:type" content="article">
的页面的应用程序链接？