擅长:python、mysql、java
<p>输入一个打印语句来查看发生了什么是很有帮助的。例如</p>
<pre><code>#! /usr/bin/env python
def flatten(nested, depth=0):
print "%d: %r" % (depth, nested)
try:
for sublist in nested:
for element in flatten(sublist, depth+1):
yield element
except TypeError:
yield nested
def main():
L = [ 1, [[2]] ]
for i in flatten(L):
print "output %s\n" % i
if __name__ == '__main__':
main()
</code></pre>
<p><strong>输出</strong></p>
<pre><code>0: [1, [[2]]]
1: 1
output 1
1: [[2]]
2: [2]
3: 2
output 2
</code></pre>