本文介绍了 pandas 数据框:截断字符串字段的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个数据框,想将每个字段截断为最多20个字符.我一直在天真地尝试以下操作:
I have a dataframe and would like to truncate each field to up to 20 characters. I've been naively trying the following:
df = df.astype(str).apply(lambda x: x[:20])
但是它没有任何作用.但是,如果我想在每个字段中添加一个"Y",则它就像一个超级按钮:
however it has no effect whatsoever. If, however, I wanted to add an 'Y' to each field, this works like a charm:
df = df.astype(str).apply(lambda x: x+'Y')
我在做什么错了?
推荐答案
,您可以使用.str.slice()方法:
演示:
In [177]: df = pd.DataFrame({
...: 'a': pd.util.testing.rands_array(30, 10),
...: 'b': pd.util.testing.rands_array(30, 10),
...: })
...:
In [178]: df
Out[178]:
a b
0 Mlf6nOsC8S6vv8OxW5ZOWifg3EoqAb XSGLdkaewwZlNeZ4uTTivi2nMQFc6S
1 0E4XCBaYFBTSalUMPGpXmke6dQGbkW KlHuVhbNgQL9HLHYQq3fEdqEIciOhX
2 URODJeLA0uLvcKBEXPyrmnnNU40MDl NaY8LURHjgmT1pRrDnbPAeLZq3ANaL
3 OYA1ahlwVtEVnDOAkZgxNkbvZ7W8Rf mIzkeLhM7SqYH17vGDzL6DJjSYftGs
4 uFC1shE02UfxS0VhDASmF8vh9XxFYX fQOxjDjFehTNT27seOtCAAPW0as9Up
5 Ja33vQym6L0Ko2Kcf8cg7OMBKMitg5 iGdCvYTyZlR23NeeTAjG1PoL8mWm3j
6 iNZdXaVpB4zXClxTLt738DY7i6xs6p q9VKg5fZdItmUpZiQrR6XW5WHmd33l
7 WWnViRRMPkbXNQOHeqGmzETDpGPRl9 t3I8Ve3ybCJcXajF8pydnwNZQWslTN
8 5oMFy2PBe1zUIE3XdraMwlrd5MKcx2 gSLtgXJwiS1HugLORXherFT4l1k5QV
9 weV8BlyJrtRbWpSCxSbj8cSyZxusFR ylLWort9o8mHWQQ3JB1Twb0xRbLhot
In [179]: df.apply(lambda x: x.str.slice(0, 20))
Out[179]:
a b
0 Mlf6nOsC8S6vv8OxW5ZO XSGLdkaewwZlNeZ4uTTi
1 0E4XCBaYFBTSalUMPGpX KlHuVhbNgQL9HLHYQq3f
2 URODJeLA0uLvcKBEXPyr NaY8LURHjgmT1pRrDnbP
3 OYA1ahlwVtEVnDOAkZgx mIzkeLhM7SqYH17vGDzL
4 uFC1shE02UfxS0VhDASm fQOxjDjFehTNT27seOtC
5 Ja33vQym6L0Ko2Kcf8cg iGdCvYTyZlR23NeeTAjG
6 iNZdXaVpB4zXClxTLt73 q9VKg5fZdItmUpZiQrR6
7 WWnViRRMPkbXNQOHeqGm t3I8Ve3ybCJcXajF8pyd
8 5oMFy2PBe1zUIE3XdraM gSLtgXJwiS1HugLORXhe
9 weV8BlyJrtRbWpSCxSbj ylLWort9o8mHWQQ3JB1T
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