string 在 Java/groovy 中将数组转换为字符串
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Convert Array to string in Java/ groovy
提问by maaz
I have a list like this:
我有一个这样的清单：
List tripIds = new ArrayList()
def sql = Sql.newInstance("jdbc:mysql://localhost:3306/steer", "root",
"", "com.mysql.jdbc.Driver")
sql.eachRow("SELECT trip.id from trip JOIN department WHERE organization_id = trip.client_id AND department.id =1") {
println "Gromit likes ${it.id}"
tripIds << it.id
}
now on printing tripids gives me value
现在打印tripids给了我价值
[1,2,3,4,5,6,]
now i want to convert this list to simple string like
现在我想将此列表转换为简单的字符串，例如
1,2,3,4,5,6
How can i do it
我该怎么做
回答by Dave Newton
Use join, e.g.,
使用join，例如，
tripIds.join(", ")
Unrelated, but if you just want to create a list of something from another list, you'd be better off doing something like a mapor collectinstead of manually creating a list and appending to it, which is less idiomatic, e.g. (untested),
不相关，但如果您只想从另一个列表中创建一个列表，您最好执行类似 amap或collect而不是手动创建列表并附加到它的列表，这不太惯用，例如（未经测试），
def sql = Sql.newInstance("jdbc:mysql://localhost:3306/steer", "root", "", "com.mysql.jdbc.Driver")
def tripIds = sql.map { it.id }
Or if you onlycare about the resulting string,
或者如果你只关心结果字符串，
def tripIds = sql.map { it.id }.join(", ")
回答by Mike Thomsen
In groovy:
在常规中：
def myList = [1,2,3,4,5]
def asString = myList.join(", ")
回答by Dónal
Use the join methodthat Groovy addes to Collection
使用Groovy 添加到 Collection的join 方法
List l = [1,2,3,4,5,6]
assert l.join(',') == "1,2,3,4,5,6"
回答by AlexR
String str = tripIds.toString();
str = str.substring(1, str.length() - 1);
回答by Sunil Kumar Sahoo
you can try the following approach to convert list into String
您可以尝试以下方法将列表转换为字符串
StringBuffer sb = new StringBuffer();
for (int i=0; i<tripIds.size(); i++)
{
if(i!=0){
sb.append(",").append(tripIds.get(i));
}else{
sb.append(tripIds.get(i));
}
}
String listInString = sb.toString();
System.out.println(listInString);
Example
例子
ArrayList<String> tripIds = new ArrayList<String>();
tripIds.add("a");
tripIds.add("b");
tripIds.add("c");
StringBuffer sb = new StringBuffer();
for (int i=0; i<tripIds.size(); i++)
{
if(i!=0){
sb.append(",").append(tripIds.get(i));
}else{
sb.append(tripIds.get(i));
}
}
String listInString = sb.toString();
System.out.println(listInString);
