Pandas - 修改每个单元格中的字符串值
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Pandas - Modify string values in each cell
提问by code base 5000
I have a panda dataframe and I need to modify all values in a given column. Each column will contains a string value of the same length. The user provides the index they want to be replaced for each value: ex: [1:3]and the replacement value "AAA".
我有一个Pandas数据框，我需要修改给定列中的所有值。每列将包含一个相同长度的字符串值。用户为每个值提供他们想要替换的索引：例如：[1:3]和替换值"AAA"。
This would replace the string from values 1 to 3 with the value AAA.
这会将值 1 到 3 的字符串替换为值AAA。
How can I use the applymap, map or apply function to get this done?
如何使用 applymap、map 或 apply 函数来完成这项工作？
Thanks
谢谢
Here is the final solution I went off of using the answer marked below:
这是我使用下面标记的答案的最终解决方案：
import pandas as pd
df = pd.DataFrame({'A':['ffgghh','ffrtss','ffrtds'],
#'B':['ffrtss','ssgghh','d'],
'C':['qqttss',' 44','f']})
print df
old = ['g', 'r', 'z']
new = ['y', 'b', 'c']
vals = dict(zip(old, new))
pos = 2
for old, new in vals.items():
df.ix[df['A'].str[pos] == old, 'A'] = df['A'].str.slice_replace(pos,pos + len(new),new)
print df
回答by root
Use str.slice_replace:
df['B'] = df['B'].str.slice_replace(1, 3, 'AAA')
Sample Input:
样本输入：
A B
0 w abcdefg
1 x bbbbbbb
2 y ccccccc
3 z zzzzzzzz
Sample Output:
示例输出：
A B
0 w aAAAdefg
1 x bAAAbbbb
2 y cAAAcccc
3 z zAAAzzzzz
回答by MaxU
IMO the most straightforward solution:
IMO 最直接的解决方案：
In [7]: df
Out[7]:
col
0 abcdefg
1 bbbbbbb
2 ccccccc
3 zzzzzzzz
In [9]: df.col = df.col.str[:1] + 'AAA' + df.col.str[4:]
In [10]: df
Out[10]:
col
0 aAAAefg
1 bAAAbbb
2 cAAAccc
3 zAAAzzzz
