如何自动缩进字符串的下一行

Question

我正在尝试使用Python编写一个程序，当遇到某些字符（例如花括号）时，它将自动缩进字符串的下一行。

例如：

public class Example{

--indent--> public static void main (String[]args){

--indent--> System.out.println("Hello");
}
}

我似乎无法掌握实现该目标所需的编码。

任何帮助将不胜感激！

Answer 1

这是一种快速而肮脏的方法。基本上，我只是遍历输入字符串（cppcode）的行并跟踪当前的缩进（tabdepth）。当我在输入行中遇到支撑时，我向上或向下增加制表符深度，然后将tabdepth个制表符添加到输出行。

cppcode = '''
public class Example{

public static void main (String[]args){

System.out.println("Hello");
}
}
'''


tabdepth = 0

for line in cppcode.split("\n"):
    depth_changed = False
    indentedline = ''.join(['\t'*tabdepth, line])
    for c in line:
        if c == '{':
            tabdepth += 1

        elif c == '}':
            tabdepth -= 1
            depth_changed = True

    if depth_changed: 
        indentedline = ''.join(['\t'*tabdepth, line])

    print(indentedline)

Answer 2

老实说，设置代码的确切方式取决于您是否正在对代码进行“漂亮打印”。大概的轮廓看起来像这样

def pretty(s):
    start = "{"
    end = "}"
    level = 0
    skip_start = False

    for c in s:
        # raise or lower indent level
        if c == start:
            level += 1
        if c == end:
            level -= 1

        if level < 0:
            raise IndentationError("Error Indenting")

        if c == "\n":
            skip_start = True # I'm bad at naming just a flag to mark new lines

        if c.isspace() and skip_start:
            pass #skip whitspace at start of line
        else:
            if skip_start:
                print("\n", "  " * level, end="") #print indent level
                skip_start = False
            print(c, end = "") #print  character

pretty('''
public class Example{



public static void main (String[]args){
if (1==1){
    //do thing
//do other thing
             // weird messed up whitespace
}else{
System.out.println("Hello");
}
}
}
''')

将输出

 public class Example{
   public static void main (String[]args){
     if (1==1){
       //do thing
       //do other thing
       // weird messed up whitespace
     }else{
       System.out.println("Hello");
     }
   }
 }