python怎么判断输入的是不是数字_python如何判定字符串的前几个字符是不是数字？...

zeppe

if re.match(&＃39;^\d&＃39;, line):

#doWhatYouWant

else:

#this is the line doesn&＃39;t start with number

seu-ljc

引用回帖:

zeppe at 2015-04-04 09:17:37

if re.match(&＃39;^\d&＃39;, line):

#doWhatYouWant

else:

#this is the line doesn&＃39;t start with number

牛牛&＃xff0c;这个难道不是判断此行有没有数字&＃xff1f;不是判断此行前几位是不是数字开头吧&＃xff1f;

请指教~

me_yu

from pylab import *

import re

t&＃61;open(&＃39;TH.txt&＃39;,&＃39;w&＃39;)

fileHandle&＃61;open(&＃39;1.txt&＃39;,&＃39;r&＃39;)

line&＃61;fileHandle.readline()

while not(&＃39;List&＃39; in line):

line&＃61;fileHandle.readline()

done &＃61; 0

while not done:

if line!&＃61;&＃39;\n&＃39;:

line&＃61;fileHandle.readline()

if line&＃61;&＃61;&＃39;&＃39;:

break

temp &＃61; &＃39;&＃39;

for i in line:

if i.isdigit() or i &＃61;&＃61;&＃39; &＃39; or i &＃61;&＃61; &＃39;\n&＃39;:#每行拆分到每个字符判断就好了&＃xff0c;不是数字的就排除

temp&＃43;&＃61;i#排除非数字后再重新组合

t.write(temp)

else:

done&＃61;1

fileHandle.close()

t.close()

seu-ljc

引用回帖:

me_yu at 2015-04-04 21:32:37

from pylab import *

import re

t&＃61;open(&＃39;TH.txt&＃39;,&＃39;w&＃39;)

fileHandle&＃61;open(&＃39;1.txt&＃39;,&＃39;r&＃39;)

line&＃61;fileHandle.readline()

while not(&＃39;List&＃39; in line):

line&＃61;fileHandle.readline()

done &＃61; 0

while not done: ...

牛牛&＃xff0c;按你的代码得出来的结果如下&＃xff1a;

0287286028902920296028203170205082355

1287286028902920296028203170292082356

2287286028902920296028203180471082357

3288286028902920296028203180445082358

4288286028902920296028203180377082359

5288286028902920296028203180284082400

6287286028902920296028203170273082401

。。。

空格没有了。。。想要的结果是

0 28.7 28.60 28.90 29.20 29.60 28.20 31.70 20.50 8 23 55

1 28.7 28.60 28.90 29.20 29.60 28.20 31.70 29.20 8 23 56

2 28.7 28.60 28.90 29.20 29.60 28.20 31.80 47.10 8 23 57

3 28.8 28.60 28.90 29.20 29.60 28.20 31.80 44.50 8 23 58

4 28.8 28.60 28.90 29.20 29.60 28.20 31.80 37.70 8 23 59

5 28.8 28.60 28.90 29.20 29.60 28.20 31.80 28.40 8 24 00

还望送佛送到西~计算机大牛给的思路确实&＃xfffd;

&＃xff0c;

seu-ljc

引用回帖:

me_yu at 2015-04-05 00:08:21

if i.isdigit() or i &＃61;&＃61;&＃39;        &＃39; or i &＃61;&＃61; &＃39;\n&＃39;:#要保留什么字符在这里加进去就好了 比如还有点&＃xff08;.&＃xff09;和换行符就这样再加一个 i &＃61;&＃61; &＃xff07;.&＃xff07; or i &＃61;&＃61; &＃xff07;\n&＃xff07;

...

经你点拨&＃xff0c;我用了此句if i.isdigit() or i &＃61;&＃61;&＃39;\t&＃39; or i &＃61;&＃61; &＃39;.&＃39; or i&＃61;&＃61;&＃39;\n&＃39;:

得到结果如下&＃xff1a;

0 28.7 28.60 28.90 29.20 29.60 28.20 31.70 20.50 82355

后面的82355并没有分成 8 23 55&＃xff1f;

我之前的方法temperaturetime&＃61;re.findall(r&＃39;\d*\.?\d&＃43;&＃39;,line)可以实现结果8 23 55&＃xff0c;可惜不能实现判定字符串的前几个字符是不是数字&＃xff1f;

所以不知完全按你的思路&＃xff0c;如何把82355 分开&＃xff0c;后面要对这些数字进行处理&＃xff0c;故而必须要将82355 分开~

me_yu

引用回帖:

seu-ljc at 2015-04-05 00:18:27

经你点拨&＃xff0c;我用了此句if i.isdigit() or i &＃61;&＃61;&＃39;\t&＃39; or i &＃61;&＃61; &＃39;.&＃39; or i&＃61;&＃61;&＃39;\n&＃39;:

得到结果如下&＃xff1a;

0 28.7 28.60 28.90 29.20 29.60 28.20 31.70 20.50 82355

后面的82355并没有分成 8 23 55&＃xff1f;

我之前的方 ...

#稍微动下脑筋就可以解决的啊&＃xff0c;代码如下&＃xff1a;

from pylab import *

import re

t&＃61;open(&＃39;TH.txt&＃39;,&＃39;w&＃39;)

fileHandle&＃61;open(&＃39;1.txt&＃39;,&＃39;r&＃39;)

line&＃61;fileHandle.readline()

while not(&＃39;List&＃39; in line):

line&＃61;fileHandle.readline()

done &＃61; 0

while not done:

if line!&＃61;&＃39;\n&＃39;:

line&＃61;fileHandle.readline()

if line&＃61;&＃61;&＃39;&＃39;:

break

temp &＃61; &＃39;&＃39;

temperaturetime&＃61;re.findall(r&＃39;\d*\.?\d&＃43;&＃39;,line)

line &＃61; line.replace(&＃39;:&＃39;,&＃39; &＃39;)#将冒号替换成空格

for i in line:

if i.isdigit() or i &＃61;&＃61;&＃39; &＃39; or i &＃61;&＃61; &＃39;\n&＃39; or i &＃61;&＃61; &＃39;.&＃39; or i &＃61;&＃61;&＃39; &＃39;:#将判断冒号条件改为空格条件

temp&＃43;&＃61;i

t.write(temp)

else:

done&＃61;1

fileHandle.close()

t.close()