將下面的list保留4位小數輸出
a = [0.00256,0.00265,0.00254,0.00258]
1，輸出之後是浮點數
a = [0.00256,0.00265,0.00254,0.00258]
b = [round(i,4) for i in a]
>>> b
0.0026
0.0027
0.0025
0.0026
值得注意的是round函數有時候結果並不像我們想的那樣，比如下面的計算
data是一個數據數組，其中第一行第4列爲0.0086809999999999995
上面的結果表明還是使用float(’%.4f’%data[0,3])靠譜。
2，輸出之後是字符串
除了使用上面的%.3f%data這種方法外還可以用.format形式
a = [0.00256,0.00265,0.00254,0.00258]
c = ['{:.4f}'.format(i) for i in a]
Out: ['0.0026', '0.0027', '0.0025', '0.0026']