Ruby：如何仅在字符串中大写第一行

Question

我似乎无法获得如何大写字符串的第一行

"1. walking down the street
2. to go to the store
3. to buy some groceries"

Answer 1

String#sub仅替换第一场比赛。使用此功能：

>> s = "1. walking down the street
2. to go to the store
3. to buy some groceries"

>> puts s.sub(/.*/, &:upcase)
1. WALKING DOWN THE STREET
2. to go to the store
3. to buy some groceries

>> puts s.sub(/.*/) { |line| line.sub(/[a-z]/i, &:upcase) }
1. Walking down the street
2. to go to the store
3. to buy some groceries

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根据评论

更新：

>> puts s.gsub(/.*/) { |line| line.sub(/[a-z]/i, &:upcase) }
1. Walking down the street
2. To go to the store
3. To buy some groceries

Answer 2

<强> INPUT：

1. walking down the street
2. to go to the store
3. to buy some groceries

使用此功能：

.sub(/[a-zA-Z]/){|c| c.upcase}

<强>输出：

1. Walking down the street
2. to go to the store
3. to buy some groceries